Preheat the oven to 350°F. Place the beans, ¼ cup of chocolate chips and the oil in a food processor, then cover it and process until blended. Add the eggs, brown sugar, cocoa, vanilla, baking powder and salt, then cover and process until smooth.
Transfer this blend into a parchment-lined 8-inch square baking pan, then sprinkle the remaining chocolate chips over the top. Bake for 20 to 25 minutes, or until a toothpick inserted in the center comes out clean. Cool on a wire rack, cut into bars and serve.
