here is the uncomplicated recipe
Box of brownie mix, doesnt matter which one, I got mine at Walgreens along with the other ingredient
1 can black beans 15.5 ounces
in blender or food processor, mix the brownie mix and the entire content of blackbeans until batter is smooth
pour into a 9X9 greased baking dish and bake according to box instruction.
when done baking let stand atleast an hour because the brownies will be soft due to all the moisture from the beans.
serve and watch the brownie disappearing act