Bars and Brownies

Sourdough Brownies

Sourdough Brownies

I’ve been teasing everyone with my sourdough brownie trials on instagram lately. I got a big box of Guittard chocolate, kindly gifted by them, and I wanted to bake something super chocolatey with it! When I put the question on my stories, everyone was intrigued by the idea of sourdough brownies (as I had mentioned wanting to make them) so I decided to go ahead and do it!

You might wonder what the point of making sourdough brownies is. Regular brownies are EXCELLENT, why add sourdough into the mix? For me, it’s another delicious way to use up the sourdough discard that comes along with feeding a sourdough starter. You end up with a lot of sourdough going in the bin (as the nature of feeding it means you discard some every day). I’ve been trying to come up with easy, everyday recipes to use this discard instead of chucking it in the bin.

Sourdough Brownies

Previously I’ve made waffles and crumpets using the discard. They’re both really easy to make but not ‘everyday’ recipes. Brownies, on the other hand, are something I bake quite often. They’re probably one of my favourite homemade bakes, even though I weirdly have very few recipes for them on here! So, if I can chuck some starter into my regular batch of brownies, it’s a win-win. My brownies get a bit of tangy sourdough magic, and I use up my discard!

These brownies are my favourite kind. They have a very fudgy middle yet aren’t dense or dry. The top has a fine layer of crisp meringue – made by whipping the sugar with the eggs before folding in the rest of the ingredients. They’re crackly and sticky and delicious (especially with a scoop of vanilla ice cream and some sliced strawberries). You can freeze them in an airtight container if you need to. I hope you enjoy them as much as we have!

Sourdough Brownies

Sourdough Brownies

Yield: 16 brownies


  • 150g (5.3 ounces) dark chocolate (65-70% cocoa solids)
  • 50g (1/4 cup) unsalted butter
  • 60g (1/4 cup) vegetable oil
  • 2 eggs + 1 egg white (if you're in Europe use size 'large'. If you're in the US use size 'extra large')
  • 1/2 tsp salt
  • 150g (2/3 cup) caster sugar or granulated sugar
  • 110g (1/2 cup, packed) light brown sugar
  • 2 tbsp water
  • 1 tsp vanilla extract
  • 50g (1/2 cup) unsweetened cocoa powder
  • 120g (1/2 cup + 2 tbsp) sourdough starter (100% hydration) (see notes)


  1. Preheat the oven to 180°C/375°F fan (or 200°C (400°F) without a fan). Line a 7.5 x 9.75-inch (9 x 25 cm) rectangular or 9-inch (23cm) square brownie pan with baking paper.
  2. Break the chocolate up into chunks. Place into a medium pot with the butter and vegetable oil. Set over a low heat on the stove and stir often (to prevent it burning), until the chocolate is almost fully melted. Remove from the heat and set aside so the remaining chocolate can melt from the residual heat.
  3. This next step can be done in a stand mixer with the whisk attachment, or in a large bowl with electric beaters: Place the eggs, egg white, salt and both kinds of sugar into a large bowl (or the bowl of the stand mixer) and whisk until pale and very fluffy. Add the water and vanilla then continue to whisk until the sugar has mostly dissolved - you can tell when this has happened by rubbing some of the mixture between your fingertips, if it feels very grainy, you need to keep whisking. This will take about 10-15 minutes.
  4. Mix the cocoa powder and sourdough starter into the melted chocolate mixture until completely combined.
  5. Add this mixture to the bowl of whipped egg mixture and fold together until just combined.
  6. Pour into the prepared brownie tin and bake for 30-35 minutes (SEE NOTES IF IN THE US). The top should look dry and a toothpick inserted into the centre of the brownies should come out with a little bit of batter still stuck to it, but not LOADS.
  7. Let the brownies cool for at least 20 minutes before slicing into 16. Sprinkle with some flaky salt if you want!


  • My sourdough starter is 100% hydration and I feed it with 50% white flour and 50% dark rye flour. This recipe should work with a 50:50 wholewheat + white sourdough starter as well. The starter shouldn't be super cold as may will seize when mixed with the chocolate if it is.
  • These worked either using discard from that day's feed OR using discard that I had collected in the fridge over a period of a week.
  • Caster sugar is preferred for making these as the fine sugar crystals aid in getting that meringue-like top on the brownies. However granulated sugar will work just fine, you may need to whip the mixture for slightly longer.
  • You can double all of the ingredients to make a larger batch - just bake in a 9 x 13-inch rectangular tray. The baking time should be 35-40 minutes.
  • IF BAKING IN THE US: some people who have made this and are in America have needed to bake the brownies for twice as long! Please use your own judgement to test them and make the call on when they are done. They should be quite soft when still warm but should firm up once cooled.

Have you made this recipe?
I’d love to see how it went! Tag me on instagram @izyhossack and hashtag it #topwithcinnamon so I can have a look & reshare in my stories!

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  • Reply Natalie April 17, 2019 at 9:00 pm

    These brownies look so chocolatey and amazing! I love how decadent they are ♥

    • Reply Izy April 18, 2019 at 10:49 am

      Thanks, lovely! They’re so so good 🙂

  • Reply Cinnamon Vogue April 18, 2019 at 4:27 pm

    Don’t throw your babies away. Can’t you get them adopted by a good family? I certainly talk to my plants. At time mind you. These soughdough brownies are an interesting spin. They certainly look nice.

    • Reply Izy May 2, 2019 at 9:19 am

      haha I ended up giving them to my neighbours! So I didn’t have to throw them away, yay!! Thank you, they’re soooo good, definitely worth a try if you have any sourdough starter

  • Reply Gooey Sourdough Brownies – Bakes, Cakes and Protein Shakes April 20, 2019 at 10:08 am

    […] from Izy Hossack’s recipe) Ingredients: 150g dark chocolate 50g salted butter 60g vegetable oil 50g dark cocoa powder 120g […]

  • Reply wallflourgirl April 29, 2019 at 12:39 am

    I’ve been seriously *obsessing* about these on IG and now I’m back again to tease myself with these. They. Look. So. GOOD. I’m going to try them. I am, I swear. And then I’m going to go run around a building screaming at the top of my lungs about how wonderful they are.

    • Reply Izy May 2, 2019 at 9:17 am

      hehe really hope you like them!! One of my fave brownies I’ve ever made 🙂

  • Reply superfitbabe May 3, 2019 at 4:21 am

    WOW, sourdough brownies?! This is exactly what I need to see. What a freaking fantastic idea–integrating brownies, aka the national food on my birthday, and sourdough bread, which is my favorite type of bread! Do you think I could use vegan butter and flax eggs for this recipe to make it plant-based?

  • Reply How to make a gluten free sourdough starter from scratch - Georgeats August 13, 2019 at 6:16 am

    […] giving starter to someone else or using it to make any number of baked goods (pizza bases, waffles, brownies a-la Izy Hossack.) I think it’s important to make the connection (it took me a while) that discarding […]

  • Reply Baking Season - 2 Travelling Foodies October 16, 2019 at 1:27 am

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  • Reply stacey December 18, 2019 at 9:51 pm

    I made these and they are almost too dark, but my chocolate is a very fruity variety. I put a dollop of lightly sweetened whipped cream on them and served with cold milk. They definitely need something to mellow them a bit.

  • Reply Ellie January 27, 2020 at 11:26 pm

    I just made these and am waiting to pull them out of the oven – I’m not sure if it’s the elevation in which I live, but 30-35 minutes wasn’t nearly enough. Just a heads up for other US bakers!😊 They smell AMAZING though!

    • Reply Izy January 30, 2020 at 12:53 pm

      Thanks for that note, Ellie! Could definitely be the elevation since I have hardly any experience baking at different elevations. Hope you liked them! x

    • Reply Robyn March 24, 2020 at 1:12 am

      I too had this issue in the US. Baked them almost twice as long as recipe states. They’re delicious, but we need to eat them with a spoon…no complaints here though! 🙂

      • Reply Izy March 26, 2020 at 4:58 pm

        Thanks for letting me know! Might be an altitude thing (or possibly also because the majority of UK ovens are convection so work faster). Glad you like them!

      • Reply Izy April 6, 2020 at 11:02 pm

        Good to know! Thanks, Robyn

  • Reply Lou Cox February 15, 2020 at 11:37 am

    Hi, I’m looking forward to trying this brownie recipe, it’s really different. Never thought of trying both butter and oil!

    • Reply Izy February 15, 2020 at 3:12 pm

      Thanks, Lou! Yeah having the oil in there makes up for the fact that the sourdough incorporates more liquid into the batter 🙂 Hope you enjoy them! x

  • Reply Alyssa February 16, 2020 at 8:28 pm

    Any tips on what to use in place of an egg? Vegan here who really washes to try this! Thanks 🙏🏼

    • Reply Izy February 17, 2020 at 5:05 pm

      Hi Alyssa! I’m so sorry but with this recipe, it wouldn’t work simply substituting in an egg replacement of some kind as they are too essential for the structure of the brownie. The whole recipe would need to be redeveloped without eggs. I can definitely work on that some day but at the mo, just try swapping the flour in your fave vegan brownie recipe for double the weight of sourdough starter (e.g. if you recipe calls for 60g of flour, use 120g of starter) – that should set you off on the right path! x

  • Reply Colleen March 3, 2020 at 5:13 pm

    These were really good. I made them with my half whole wheat starter, and can imagine how the rye would add a special dimension. I reduced the sugar by just a bit, 15%, because I prefer my sweets just a tad less sweet, and I would do the same next time (there will definitely be a next time). While it’s obviously not flourless, it has the feel of a decadent flourless chocolate cake as opposed to, say, the chewiness of a brownie like Alice Medrich’s Best Cocoa Brownies, probably from the extensive whipping of the eggs. The first brownie I cut out crumbled completely apart, but the other ones have held together fine. I stuck them in the fridge and found I preferred these rich treats cold. This is a fantastic use of sourdough discard; thank you for sharing!

    • Reply Izy March 9, 2020 at 10:34 pm

      Thanks, Colleen!

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