Rich and tangy: gluten-free sourdough chocolate brownies

During lockdown, I became (and am still increasingly becoming) emotionally attached to my sourdough starter. Like a Tamagotchi or a houseplant for a just-maturing millennial, my starter has become a practice run for looking after another living being.

As I’m sure my mum can attest, however, maintaining these living beings can be a wasteful enterprise. Inherent in the sourdough starter process is the need to discard starter – it makes space to feed the yeast, refreshing and strengthening as it does so.

So what to do with the sourdough starter you’re “discarding”? First and foremost, it’s important to note that sourdough discard is not an inedible waste product, as the name implies. If you were baking a loaf every day, there’d be no need to discard – the act of using your starter counts as a discard.

There are many ways to use up discard – by baking a loaf, making crackers, adding it to banana bread or whipping up some pancakes. What it all comes down to is that your starter is healthiest when it is constantly being used and refreshed.

So, in the spirit of use it or lose it, why not make brownies? The tang of the sourdough starter subtly offsets the intense sweetness, leaving you with the most delightfully fudgy, rich and complex brownie you’ve ever had.

This recipe uses a gluten-free fine white rice flour sourdough starter that is around 110% hydration. If you have a regular starter, Izy Hossack of Top With Cinnamon has a brownie recipe that will be perfect for you. She also has a vegan option.

If you don’t yet have a gluten-free sourdough starter, you can find my guide here.

The sourdough starter should be thick and bubbly – a spoonable consistency. If it’s a new starter or very runny, save it for pancakes or crackers. These brownies are incredibly fudgy and a watery starter runs the risk of ruining a batch.

I recommend using a dark chocolate that is around 45%. Ideally, it should contain milk fat and solids, a decent amount of sugar and an emulsifier such as soy lecithin. I haven’t quite identified why these ingredients are integral to a shiny-topped brownie, but my experiments to date suggest they create the shiniest top possible.

On the note of brownie science, I’ve anecdotally discovered that using Dutch processed cocoa in this recipe creates an orange-tinged, more delicate and overall shinier brownie top. Using cocoa results in a more matte, meringue-like (but still shiny) top. You can experiment and see what you prefer.

Salt is necessary. Trust me. Vanilla bean paste also adds an incredible depth of flavour, although you could use extract in it’s place if you can’t find paste. It can also be omitted, but it does create a more well-rounded brownie.

I highly recommend, where possible, making brownies ahead of time. In an ideal world these brownies would be made the night before, or at least the morning of. Why? Because in their fresh state, they’re essentially molten cake batter. This is part of what makes them so delicious and rich, but it also means they’re very hard to handle fresh. I recommend making them the night before and allowing them to cool on the bench or in the fridge. The added benefit to this is that the flavours will further develop overnight, resulting in even better brownies.

Makes: One tray

Gluten Free sour dough brownie

‘Salt is necessary. Trust me.’ Photograph: Georgia McDermott

100g butter, dark browned
70g light brown sugar
110g caster sugar
200g dark chocolate (I use 45%, see notes)
2 extra-large eggs
16g good-quality cocoa
2 tbsp boiling water (or 1 tbs espresso and 1 water)
130g thick gluten-free sourdough discard
1 tsp vanilla bean paste
Pinch of fine salt (¼ + ⅛ tsp)

Preheat the oven to 180°C. Line a 24cm square baking tin with baking paper – leave long edges so you have a handle to pull the brownies out.

To brown the butter, place it in a small saucepan over a low-medium heat. Use a silicon spatula to stir it occasionally, discouraging the browned bits from adhering to the saucepan. Continue to cook until the butter smells very nutty and has deep brown flecks of milk solids rising to the surface.

Pour the butter into the bowl of your kitchen mixer with the whisk attachment. Add the sugars to the bowl, and whisk until they’re just combined. It should look like light, brown, wet sand at this point. Once combined, turn off the mixer and allow the butter to cool a little.

Half-fill the small saucepan you used to brown the butter with water (saves on dishes!), pop a heatproof bowl on top, and place it over a low-to-medium heat. It should not touch water – this could burn the chocolate and make it seize up. Melt the chocolate until completely smooth before removing from the heat.

Turn the mixer on to a medium-high speed (I used speed five on a Kitchenaid) and add the eggs one at a time. Stop to scrape the sides and bottom of the bowl before returning to a medium-high speed. Quite quickly, the mixture should lighten in colour and take on a meringue-like appearance and texture. It will be a light brown colour with a sheen to it. Beat the mixture for around three to four minutes or until it is visibly light and fluffy. I have had my mixture split before at this point, and although I haven’t figured out specifically why, it won’t ruin the brownies, so you can proceed as normal if this happens.

While the mixer is running, add the cocoa and boiling water to the melted chocolate. Use a spatula to just combine – any more and the mixture will stiffen. Boiling water is used to bloom the cocoa and give a more pronounced chocolate flavour (you can also use 1 tbs of espresso and 1 tbs of water to further amplify the chocolate taste).

Lower the speed of the mixer and add in the chocolate mixture. Whisk on a lower speed until totally combined. Turn the mixer off to add the sourdough starter, salt and vanilla bean paste – the paste gets stuck in the whisk if it’s moving.

Whisk again to combine before removing the bowl from the stand. Pour the brownie batter into the prepared tin and tap it on the bench a few times to remove any excess air bubbles.

Place the brownie in the oven for 20 minutes – this produces an incredibly fudgy brownie. You can cook it a little longer if you prefer your brownie well done.

They keep well in an airtight container for a few days.