Combine all ingredients except chips in a good food processor, and blend until completely smooth. Really blend well. If you don't have a food processor, a blender can also work.
Stir in the chips, then pour brownie mix into a greased 8×8 pan. Optional: sprinkle extra chocolate chips over the top.
Cook the black bean brownies 15-18 minutes, then let cool at least 10 minutes before trying to cut. If they still look a bit undercooked, you can place them in the fridge overnight and they will magically firm up
Makes 9-12 brownies.
You can also use dried black beans soaked overnight and boiled. Use a heaping cup and half.