1. Melt chocolate and butter in bowl over low heat or in microwave, add vanilla and cocoa powder.
2. In a blender, mix 1 egg and beans and blend as smoothly as possible, when smooth mix in the nuts.
3. Beat the other eggs into a fluffy consistency and fold in the bean and chocolate mixture.
4. Pour the brownie batter into a tin with parchment paper and bake for 25 "in a preheated oven at 180 ° C, let cool before serving.
Serve with a scoop of ice cream if desired.