Vegan Sourdough Brownies

Overhead view of sliced vegan sourdough brownies

The best vegan brownie I’ve ever made, these are SO fudgy with a crispy meringue-like top and a gooey centre. Such a delicious way to use up that sourdough discard too!

After people started making my original sourdough brownies recipe from last year, I had a few requests for a vegan version. I knew from past experience of brownie testing that veganising the recipe wouldn’t just be as simple as replacing the eggs with flaxseed. In brownies, the eggs form an essential part of the ‘bulk’, coagulating upon cooking to hold everything together whilst maintaining that key fudginess we all love. In my non-vegan recipe, the eggs are even more essential, providing that crackly top and a light texture.

View of the gooey centre of vegan sourdough brownies

After some experimentation I came up with a combination of ingredients to replace the eggs:

  1. Aquafaba: the obvious choice here for that meringue-y effect was aquafaba (i.e. chickpea liquid which can whip up like egg whites). I replaced the majority of the egg volume with whipped up chickpea liquid which gave me the crispy, crackly crust. However, aquafaba doesn’t coagulate on cooking so I needed to turn to some other ingredients for that…
  2. Ground almonds + cornflour: I initially used some extra flour in the recipe to provide that coagulation/bulk but that made them have a weird claggy texture, almost like a dense chocolate cake rather than a tender brownie. Ground almonds provide bulk whilst giving a moist, fudgy texture. They’re also fatty so provide the missing richness we lose from not having egg yolks. I also added in some cornstarch for that extra coagulation factor – it helps the brownies maintain more stuctural integrity once cooled but it is optional so if you don’t have any, they’ll still work.
  3. Baking soda: the last aspect the eggs provide is LIFT! We get a lil bit of that from the aquafaba but, as the aquafaba doesn’t set, we need something else to just give a slight bit of rise to the brownies. Good old baking soda to the rescue! It reacts with the acidity of the sourdough discard in the batter.
closeup of vegan sourdough brownies with aquafaba

I would say these are still different to the original brownies as they’re more fudgy and less moussey BUT they are INCREDIBLY good brownies. I think if I had been given one and didn’t know they were vegan, I wouldn’t be able to tell. Part of this is kind of down to the fact there’s not GODDAMN FLAXSEED or CHIA SEED getting stuck in my teeth when I eat them! hahaha.

How to make sourdough starter

If you haven’t got a sourdough starter yet, I have a comprehensive guide on starting and maintaining a sourdough starter right here.

Other vegan sourdough discard recipes:

NB: I’ve provided DETAILED ingredient notes below the recipe. I recommend reading through the recipe & reading the notes before you start, just so you have all the info. There are substitution notes too for if you don’t have some of the ingredients but if your Q isn’t answered there, please leave a comment/DM me/ Email me and I’ll get back to you ASAP.

Overhead view of sliced vegan sourdough brownies

Vegan Sourdough Brownies

These are the perfect vegan brownies – fudgy not greasy middle, soft melt-in-the-mouth texture and a crisp, shattering crust (thanks to whipped aquafaba). This is a great recipe for using up sourdough starter as it needs 200g (1 cup) of discard and no extra flour!
4.78 from 36 votes
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Course: Bars and Brownies
Keywords: aquafaba, brownies, chocolate, dairy free, egg free, eggless, sourdough, sourdough discard, vegan
Prep Time: 20 minutes
Cook Time: 25 minutes
Total Time: 45 minutes
Servings: 16 brownies


  • 120 g (1/2 cup) aquafaba (chickpea/black bean/kidney bean water) (see notes)
  • 1/4 tsp cream of tartar , optional
  • 250 g (1 cup + 2 tbsp) caster sugar (i.e. superfine sugar) or granulated sugar
  • 100 g (7 tbsp) vegan block 'butter' (75% fat content minimum)
  • 150 g (5.3 ounces) dark chocolate, broken into small chunks (60-70% cocoa content)
  • 200 g (1 cup) sourdough discard (100% hydration)
  • 1 tsp vanilla extract
  • 50 g (1/2 cup) unsweetened cocoa powder I used Guittard cocoa rouge
  • 70 g (3/4 cup) ground almonds (almond flour)
  • 30 g (3 tbsp) cornflour (cornstarch) optional (see notes)
  • 1/4 tsp bicarbonate of soda (baking soda)
  • 1/4 tsp fine table salt
  • flaky salt , for sprinkling (optional)


Whisk the aquafaba:

  • Place the aquafaba and cream of tartar (if using) in the bowl of a stand mixer fitted with the whisk attachment (or in a large bowl, if using a handheld electric whisk). Whisk on high speed until it becomes a thick pale foam, like whipped egg whites.
    120 g (1/2 cup) aquafaba, 1/4 tsp cream of tartar
  • Whilst continuing to whisk, add the sugar a few tablespoons at a time.
    250 g (1 cup + 2 tbsp) caster sugar (i.e. superfine sugar) or granulated sugar
  • Once all the sugar has been added, continue to whisk for 5 minutes more to ensure as much sugar as possible has dissolved. The mixture will still feel slightly grainy if you rub some of it between your fingertips (if it feels VERY grainy, keep whisking to allow more of the sugar to dissolve). It should look glossy, thick and opaque white, like egg whites whisked to semi-stiff peaks.
  • NB: I've noticed that sometimes the aquafaba doesn't get AS thick as egg whites after whisking, i.e. it doesn't hold a peak when the whisk is lifted out. But as long as the mixture is opaque and roughly tripled in volume when you're done whisking, it should be fine to use.

Melt the chocolate & butter:

  • Place the vegan butter and broken up chocolate into a small pot and place over a low heat. Stir until almost fully melted. Remove from the heat and set aside so the residual heat can melt it all fully.
    100 g (7 tbsp) vegan block 'butter', 150 g (5.3 ounces) dark chocolate, broken into small chunks
  • Once fully melted, stir the sourdough discard and vanilla extract into the pot of melted chocolate/butter mixture. It may look kind of split/grainy but this is fine.
    200 g (1 cup) sourdough discard, 1 tsp vanilla extract

Combine & Bake:

  • Preheat the oven to 180°C (350°F) fan or 200°C (400°F) non-fan. Line a 7.5 x 9.75-inch (19 x 25 cm) rectangular OR an 8 or 9-inch (20 or 23cm) square brownie pan with baking paper.
  • Mix around 1/4 of the whisked aquafaba into the melted chocolate mixture. You don't have to be gentle here as this step is to help loosen the texture of the chocolatey mixture.
  • Now pour that loosened chocolatey mixture into the bowl of whisked aquafaba. Sift the cocoa powder, ground almonds, cornflour, bicarb and salt on top (see notes if you don't have a sieve).
    50 g (1/2 cup) unsweetened cocoa powder, 70 g (3/4 cup) ground almonds, 30 g (3 tbsp) cornflour (cornstarch), 1/4 tsp bicarbonate of soda (baking soda), 1/4 tsp fine table salt
  • Use a silicone spatula to fold the mixture together gently, trying to maintain as much of that air in there as possible. Make sure you get right to the bottom of the bowl and scrape the sides too!
  • Pour the batter into the prepared pan and bake for 25-30 minutes – the top should look dry, matte and the brownies shouldn't wobble when you shake the pan. If you insert a toothpick into the centre, it should come out with some thick, gooey batter (NOT loose, drippy batter!) attached to it.
  • Remove from the oven and run a knife around the edges whilst they're hot to loosen any bits which may be stuck. Leave to cool for 20-30 minutes before removing from the tray and cutting into squares. They will sink in the centre as they cool so may crack a bit as this happens. You can sprinkle them with some flaky salt as well now.
    flaky salt


Ingredients notes:
Aquafaba: This is the liquid from a can of cooked beans. I tested these brownies with the liquid from can of chickpeas and black beans (Sainsbury’s own brand). Both worked great. I like to make sure I shake the can a lot before I open it & drain off the aquafaba which helps to dislodge the sediment from the bottom of the can (which I believe helps the aquafaba to whip up more reliably). If your aquafaba isn’t whisking up properly, try reducing it over a low heat until halved in volume before measuring and using in the recipe. Also, note that aquafaba definitely takes longer to whisk into a stiff foam than egg whites do, so give it some time!!! A stand mixer is the best option here as the extra power makes it whip up in no time whereas my experience using hand-held whisks is that it takes longer to reach the right consistency.
Cream of tartar: I add this to help stabilise the aquafaba foam which, in the end, leads to slightly less sunken brownies. However, I’ve tested it multiple times without COT and they’re just as good, probably just a bit fudgier in the end.
Caster/ superfine sugar: golden caster sugar works here as well as white caster sugar. If you can’t get this, try blitzing granulated sugar in a food processor or blender until fine (let it settle before removing the lid!). Likewise, powdered sugar (icing sugar) works – just make sure you’re using the same weight (so if you’re measuring by volume you’ll need to adjust the number of cups). Otherwise, just use granulated sugar – this means you’ll probably have to whip the mixture for longer and you may not get as fine a texture.
Vegan butter: I used Naturli vegan block (from Sainsbury’s in the UK) which is a solid block ‘butter’ with a fat content of 75%. DO NOT use a low fat margarine here!
Vegan dark chocolate: I used a Guittard 70% chocolate here but Pico is also a great brand of vegan chocolate to use. Otherwise, check the packet of your chocolate to ensure it’s vegan – most dark chocolates around 70% cocoa content already are dairy-free.
Sourdough discard: This isn’t leavening the brownies so it does not need to be active. I save my discard in the fridge in a lidded container for a week or two and then use it for baking. 100% hydration means that your sourdough is fed with equal weights of water and flour. My sourdough starter is 50:50 rye and white wheat flour but an all white starter, or a 50:50 white/wholemeal wheat flour starter will also work.
Ground Almonds: Other good substitutes are ground hazelnuts or ground cashews. If you can’t do nuts, try ground sunflower seeds. You can make your own by pulsing nuts/seeds in a food processor or blender until mealy.
Cornflour: These do work without the cornflour in them but they will be a bit softer and more fragile. The cornstarch just helps bind things together a bit better but if you don’t have any, they will still work out.
Method notes:
No sieve: instead, combine the cocoa powder, ground almonds, cornflour, bicarb and salt in a small bowl. Stir together with a whisk or a fork to remove any lumps.
Tried this recipe?Let me know how it went! Mention @izyhossack or tag #topwithcinnamon!

44 thoughts on “Vegan Sourdough Brownies”

  1. This is very new to me, sourdough in brownies? What is the reason in general for adding it?

    I will definitely give this recipe a go, I still have aquafaba left (frozen) and we always have sourdough at hand, so this should be interesting!

    • I add the sourdough as a way of using up my discard. If I’m not baking bread then I don’t want to chuck the ‘discard’ bit when I’m feeding it so I save it up in a tub in the fridge. Depending on the age of your discard, it can also add a little bit of tang to the brownies which is delish with the chocolatey flavour. I also find that as discard has a more broken-down gluten situation (due to the fermentation) it makes for a more tender baked good. Lastly, some people actually find sourdough much easier to digest so it makes them feel better to consume a fermented wheat flour rather than straight up flour. So there’s many reasons to use it in your baking!

  2. Hey! Excited to try this…but I don’t have vegan butter, can I just use a vegetable oil as you melt the butter anyway?

    • I don’t know if oil would work here. Yes, you do melt the butter but the thing is, once the brownies are baked + cooled that fat re-solidifies. I have a feeling that using just oil here will make for a greasy brownie so I would only recommend using a solid block ‘butter’.

      • I’ve made these twice now, Once with vegetable oil and once with coconut oil. Both worked and were delicious. The vegetable oil one was def more gooey, but not too greasy 🙂 Making them for a third time today!

        • Hi, Michelle! As you tried both ways, would you say vegetable oil works better than coconut oil for this recipe? Which veg oil did you use? Unfortunately I also don’t have access to vegan butter

  3. Hi Izy, looks great can’t wait to try! I’m only feeding my starter once a week at the minute is will take me a while to get 1 cup
    of discard! Is it ok to leave in the fridge for a couple of weeks and then bake with it? Thanks ?

    • Yes should be fine! I’ve kept mine in the fridge for several weeks before and it has been okay!

  4. You list cornflour but then call it corn starch….which is it? Can’t wait to make these!!

    • They’re the same thing in the UK (/ cornstarch is the American name, cornflour is the British name)

  5. Thank you so much for this recipe!
    I made these the other day and they’re the best brownies I’ve ever tried. I love how you get creative for us and develop vegan recipes and you can really tell you’ve put a lot of thought and time into this!

    • Thank you so much, Patricia! So glad to hear you liked them and it means so much that you appreciate the work I put into developing recipes 🙂

  6. Hi Izy! Thank you for make another sourdough brownie recipe, and this time it’s vegan, allergic-friendly and helps to reduce food waste! I read that if you doesn’t have COT, then you can substitute it with lemon juice. Do you think it would be the same, if I this that, for this recipe?

  7. 5 stars
    These are definitely the best brownies I’ve ever had (and my non-vegan roommate agreed!). They are perfectly chocolatey and fudgey inside with a slightly crunchy top. I am located in the US and did have to bake them a little longer than instructed (around 37 minutes) as noted in the recipe. These are really so delicious and I’ll definitely be making them again!!

  8. These are great. We’ve been enjoying the “regular” brownies, but since we’re all leaning a little more vegan lately, decided to try these. They are delicious! Directions were clear and result was very similar to your pictured result. We made no substitutions and I was amazed by how the aquafaba whipped up to a perfect meringue when the sugar was added. Very cool, delicious vegan option.

  9. 5 stars
    First time using the aquafaba and other tweaks to make this vegan. Great recipe and delicious result.

  10. 5 stars
    Wow, I didn’t expect too much, but these vegan brownies are really, really good! They are fudgy, with the right amount of sugar, not too sweet, not too bitter, and they have a wonderful crackling top, will be making them again as we often have sourdough discards.
    Mine didn’t sink that much and next time I will bake them a little less than 25 minutes (I’m in Germany).

  11. I just made these are they are my favourite brownies EVER. Even better, it uses my starter! I must admit that i didn’t have vegan butter, so used normal butter (pls don’t hate). The texture and taste is just fantastic and they are the BEST thing the next day when they’re a little bit more fudgy, served a little bit warm with banana nicecream and a sprinkle of salt! Thank you, thank you, thank you. Now, the hardest thing will be NOT to make these every week…!

    • hahahah of course I wouldn’t hate you for using dairy butter! I’m always a fan of people using what they have/what they like in recipes 🙂 So pleased you like the recipe!!

  12. 5 stars
    Amazing. SUper fudgy and just THE BEST served with a sprinkle of salt and some banana icecream. Thank you!

  13. 5 stars
    My sourdough discard was with graham- and oat flour. I didn’t have COT, so I used baking powder, because there was baking soda in the recipe, and I substituted cornstarch with tapioca-starch. They didn’t fall apart and you can’t taste the aquafaba at all! The brownies were so delicious, all my friends & family liked them <3

  14. These are delicious, thankyou hit developing the recipe. Second time baking them! Can you freeze these?

    • So glad you like them! Yes they should freeze well. I would wrap in baking paper & put them into a resealable sandwich bag to freeze.

    • Hi, just made these today and they’re really nice! How long do they store for and how are they best stored?

      • I’d say they keep for around 5 days in an airtight container. If your kitchen is hot though, keep them in the fridge and they’ll last better

  15. 5 stars
    Made these, v yummy – super fudgy and gooey. The only thing I would say is that they collapsed A LOT when I took them out of the oven – quick bit of internet googling says this is due to insufficient gluten and over whisking. So not cakey in the slightest! But if you like them fudgy – these are your brownies!

    • The almond flour provides a very different texture than grain-based flours. You can grind up any nut you like into a ‘flour’ using a food processor or blender and use instead of the ground almonds. If you can’t do nuts, dry using sunflower seeds instead

  16. I’ve just stumbled upon your recipe. While I haven’t made them yet but I can’t tell it will be yummy because of the care and intelligent thoughts you’ve taken in replacing, replicating to provide texture, rise, mouthfeel etc. I truly thankyou for ur generous spirit. I can’t wait to bake these, placing the starting with flour and water instead because I don’t have any starter and can’t wait that long to make it ?

  17. I wanna try this recipe but i don’t have a chocolate bar with this much of cocoa. Do you think it is possible to lower the sugar of the recipe based on the percentage of cocoa and sugar of the chocolate bar?

  18. 5 stars
    This is my first time baking with both sourdough starter and aquafaba. I am so impressed! these turned out so well!! They are super fudgy and delicious.

    I didn’t have vegan butter with enough fat content to try to make these but I hope to repeat it when I do!

    thanks for the recipe!

  19. 5 stars
    incredible!! i love a good way to use up my sourdough starter + love that u can actually taste it too!!! its so cool, delicious. i love it. worth all the steps : )

  20. I’m excited to try a sweet discard recipe!

    My discard is 50% hydration so do I need to adapt any of it? I also don’t have vegan butter so was going to try and sub with coconut oil.

    • I loved it! I done it with oil, too. Just use little less oil or it will make the brownies more moist. But this is so nice, thank you!

  21. I’m new to sourdough and temporarily vegan (usually vegetarian). I made these last night and they are wonderful.

    One thing I really love about this recipe is the care you have taken to experiment with ingredients to replicate a normal brownie. I really respect your attention to that detail.

    The brownies are unbelievably light and SOOOOOO chocolatey. They went down extremely well. I’m now going to delve more into your website, as I’ve not come across it before. Thank you, Izy!

  22. My boyfriend and I made these brownies this weekend and I am quite frankly amazed at how brilliantly they’ve turned out! In my opinion, they are now at their best a couple of days after baking. We used half cocoa and half cacao (purely because we ran out of cocoa) and we really enjoyed that combination. Already planning to make them again pretty sharpish!

  23. 5 stars
    these are so good! I had to had whip the aquafaba which took probably 20 minutes and still didn’t achieve semi stiff peaks, but they still turned out perfectly. A bit more cakey than fudgey, but perfectly fluffy and soo chocolatey. i love them.

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