Black bean brownies

2 cups black beans
200g dark cooking chocolate
1 cup unsalted butter
1 tbsp instant coffee powder
2 tbsp boiling water
1 cup macadamias, chopped
pinch salt
4 large eggs
1 cup soft brown sugar
1 tsp vanilla essence
extra 1/2 cup macadamias
coocoa powder to serve

1. Put beans in a large bowl. Cover completely with water, then leave to soak overnight.
2. Drain beans, then put in a large pan. Cover with water to 5 cm above beans and bring to the boil over a medium heat. Reduce heat to low and simmer for 40 minutes or until tender. Drain, rinse in cold water and spread on a tray to cool.
3. Preheat oven to 170C. Line an oven tray with baking paper. Melt chocolate and butter in a microwave.
4. Combine coffee and boiling water, then use a metal spoon to stir into chocolate mixture. Cool slightly.
5. Put beans, nuts and salt ina blender and roughly blend. Beat eggs, sugar and vanilla in the large bowl of an electric mixer for 5 mins or until combined. Gradually add choc mixture and whisk until combined. Fold in bean mix and extra nuts. Spoon evenly into prepared tray then bake for 40-45 minutes.
6. Cool brownie in tray for 20 minutes. Transfer to a board and cut into slices. Dust with cooca and serve.