Combine both of the flours, the bicarb (or ammonia), salt, cinnamon and sugar in a medium bowl. Bash the cardamom pods in a pestle and mortar to break them open, push out the seeds and discard the papery skin. Grind the seeds in the pestle and mortar into a fine powder. Add this to the bowl of dry ingredients too. (If you want to make the dough in a food processor, see the recipe notes below)

Cut the butter into smallish cubes and add to the bowl. Use your fingertips to rub the butter into the dry ingredients until no large lumps of butter remain and the mixture is crubmly. Add the golden syrup, milk (start with 2 tbsp for now) and vanilla extract to the bowl. Use a spoon to stir together to make a moist, soft dough. If it seems too dry, drizzle in a bit more milk and knead it in with your hands.

Divide the dough in half, form into 2 balls and then flatten into disks. Place into a reusable sandwich bag and chill for at least 30 minutes so the dough can firm up.

Preheat the oven to 160°C fan (320°F) and grab a large cookie sheet/baking tray (I like to use one without a rim for this but a rimmed sheet is fine).

Cut a piece of baking paper to the size of your baking tray. Place the baking paper on your work surface and dust with some plain flour. Take one disk of dough from the fridge and place onto the baking paper. Dust with more flour. Use a rolling pin to roll it out until the dough is about 2mm thick, dusting with flour as needed to prevent it sticking to the rolling pin.

Cut into 5cm (2-inch) squares and leave them connected like this. We will bake the dough as one big sheet so that the crackers stay in a neat shape, then break them up once they're baked! Dock the crackers all over with a fork (or the small end of a chopstick if you want a more authentic look).

Lift the sheet of dough up with the baking paper still underneath it, and lay onto your cookie sheet. Get them into the oven and bake for 10 minutes. Rotate the cookie sheet so that the crackers can bake evenly. Lower the oven temperature to 140°C fan (280°F) and bake for a further 10 minutes.

Remove from the oven and break along the score lines into squares. Allow to cool and then transfer to an airtight container. Repeat with the remaining disk of dough as above.

They will keep for a couple of weeks like this, if they start to soften just lay on a cookie sheet in an oven at 120°C fan (250°F) and bake for 5-10 minutes until crisp again.