2 1/2 cups all-purpose flour  | 
                                                2 teaspoons baking powder  | 
                                                1/2 teaspoon baking soda  | 
                                                1/4 teaspoon salt  | 
                                                2 cups shredded unpeeled zucchini  | 
                                                1 cup sugar  | 
                                                1/4 cup unsweetened cocoa  | 
                                                1 teaspoon cinnamon  | 
                                                1/2 cup vegetable oil  | 
                                                1/4 cup fat-free buttermilk  | 
                                                2 teaspoons vanilla  | 
                                                3 egg whites or 1/2 cup egg substitute  | 
                                                1 tablespoon powdered sugar  |