Preheat oven to 350 degrees. Spray a 8-inch square baking dish with cooking spray (or brush with oil) and set aside.
Put black beans in a food processor and process until smooth.
Add eggs, oil, cocoa, baking powder, vanilla and brown sugar, and process until completely blended. (Note: You may need to stop and scrape down the sides a couple times during this step).
Add ¼ cup chocolate chips and pulse 5 times.
Pour mixture in prepared baking dish. Sprinkle top with remaining chocolate chips.
Bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean. Put on a wire rack and let cool completely before serving.
Recipe by Alida's Kitchen at https://www.alidaskitchen.com/2012/08/08/black-bean-brownies/