Prep time 30 mins Cooking time 20 mins Makes 16
150g unsalted butter 300g caster sugar 1/4 tsp salt 110g cocoa powder 1/2 tsp vanilla extract 2 eggs, straight from the fridge 120g plain flour icing sugar and fresh berries, to serve 1 Preheat the oven to 160°C. Place the butter, sugar, salt and cocoa powder in a large heatproof bowl. Place the bowl over a pan of simmering hot water. Do not let the bottom of the bowl touch the water. Stir gently until the butter has melted and everything is combined. The mixture should be smooth, but slightly gritty. Set aside to cool. 2 Line a 20cm square tin with greaseproof paper. When the mixture is cool, beat in the vanilla. Add the eggs, one at a time, whisking between each addition, until the mixture is smooth. 3 Beat in the flour until the mixture is smooth and slightly glossy, ensuring any flour stuck to the bottom of the bowl is incorporated. Pour into the tin and bake in the bottom half of the oven for 20 minutes. 4 Remove from the oven, allow to cool completely, then take out of the tin and remove the paper. Slice into 16 squares. 5 Dust with icing sugar and serve with fresh berries.