Spray muffin pans or loaf pans with cooking spray. Preheat the oven at 350 degrees F. Put bananas into a food processor bowl or blender. Secure lid and blend until smooth. Scrape banana into a mixing bowl and combine with eggs and oil. In another mixing bowl, combine flour, sugar, cocoa, baking soda, salt, and baking powder. Add banana mixture, and stir until moistened. Stir in raisins. To make Mini-Muffins: spoon 1 tablespoon of batter into each muffin pan cup. Bake for 12 to 15 minutes. Cool muffins before popping them out. To make Regular Muffins: spoon 1/3 cup of batter into 10 to 12 prepared muffin pan cups. Bake for 20 to 25 minutes. To make a loaf: pour the batter into a prepared 9" x 5" loaf pan. Bake for 55 to 60 minutes. Cool for 10 minutes before removing from pan. Cool bread completely before slicing.