Preheat the oven to 350 °F.

Thoroughly rinse and drain the black beans. Grind the flax seeds in a food processor or use store-bought ground flax seeds. Add 8 tablespoons of water and set aside to thicken for about 2 minutes. Then make the batter: Combine all ingredients except the chocolate chips in a food processor and process until smooth.

Lightly grease a baking tray and pour in the batter. Add the chocolate chips to the batter and spread evenly. Stir in one tablespoon of peanut butter with a fork.

Bake for about 40 minutes. Don't worry if the brownies appear to still be a bit soft, they'll get harder once they cool down. Allow the brownies to cool down.

Once the brownies have cooled down, melt the chocolate either in the microwave or over the stove. Melt the peanut butter in a small pot. First put about half of the melted peanut butter on top, then cover them with the melted chocolate and immediately sprinkle with the crumbled Oreos and the peanuts. Add the rest of the peanut butter on top. Let the topping harden for about an hour before you cut the brownies in pieces.