Preheat the oven to 300 F. Grease or spray an 8x8" baking pan.
Drain and rinse black beans thoroughly. This is best done in a colander.
Combine black beans, sugars, chopped nuts, cocoa powder, butter, baking powder and salt in a food processor.
Process until smooth, stopping once or twice to scrape down sides with a spatula if necessary.
Add in eggs and pulse/process to combine.
Pour mixture into prepared pan.
Bake for 35 - 40 minutes or until center is firm and the edges get slightly crisp.
Cool on a wire rack.
To serve, cut into bite sized squares and sprinkle with powdered sugar. Enjoy!
Store covered in fridge.