Preheat oven to 350 F. Grease an 8 x 8-inch baking pan. In a food processor or blender, purée black beans, eggs, oil, and vanilla extract for 90 seconds. Transfer to a medium bowl. In a small bowl, combine cocoa powder, sugar, baking powder, and salt. Pour dry ingredients into wet ingredients and mix with a spatula until well combined. Stir in chocolate chips, then pour batter into greased baking pan and pop in the oven for 30 minutes, until edges start to pull away from the pan. Cool before dusting with powdered sugar and cutting into squares.
Per serving: 361 calories, 11 grams fat (3.5 grams saturated fat), 62 milligrams cholesterol, 92 milligrams sodium, 55 grams total carbohydrates, 8 grams fiber, 14 grams protein.