250g 70% cocoa chocolate
250g unsalted butter
300g golden caster sugar
3 large eggs, plus 1 extra egg yolk, lightly beaten
60g plain flour
½ tsp baking powder
Pinch of salt
60g good quality cocoa powder
100g walnuts (optional)
1. Pre-heat the oven to 180C, and line a 23cm x 23cm baking tin with baking parchment.
2. Set a bowl over, but not touching, a pan of simmering water, and add 200g of the chocolate, broken into pieces. Allow to melt, stirring occasionally, and then remove from the heat immediately.
3. Meanwhile, beat the butter and sugar together until light and fluffy, and break the rest of the chocolate into chips.
4. With the mixer still running, gradually add the eggs, beating well between each addition to ensure it’s thoroughly incorporated before pouring in any more. Leave mixing on a high speed for five minutes until the batter has a silky sheen, and has increased in volume.
5. Remove the bowl from the mixer, and gently fold in the melted chocolate and chocolate chips with a metal spoon, followed by the sifted flour, baking powder, salt, cocoa powder and walnuts.
6. Spoon the mixture into the tin, and bake for 30 minutes. Test with a skewer; it should come out sticky, but not coated with raw mixture. If it does, put it back into the oven for another 3 minutes, then test again. Prepare a roasting tin of iced water.
7. When the brownies are ready, remove the tin from the oven and place in the cold water bath. Leave to cool for an hour before cutting into squares. Store in an air-tight container; they’re even better the next day.