85g chilli-flavoured chocolate (or plain chocolate), chopped into chunks
Heat oven to 180C/160C fan/gas 4. Lightly grease a 20 x 30cm brownie tin and line with baking parchment. Blitz the beans and vanilla, 1/2 tsp salt and 2 eggs with a stick blender until completely smooth.
Put the butter and sugar in a bowl with the cocoa and remaining eggs, and beat with an electric whisk until creamy. Start off slowly, then increase the speed as you mix (so you don’t get covered with cocoa!). Beat in the baking powder, then stir in the bean mixture and fold in the chocolate chunks.
Scrape the mixture into the tin with a spatula, level it and bake for 25 mins until firm to the touch. Leave to cool, then cut into squares. Will keep for a few days in a tin at room temperature, and 1 week in the fridge.