Prep: Heat oven to 350°. Line muffin cups (2.5 in.) with paper bake cups.

Make batter: Combine dry ingredients (baking powder, cocoa, sugar, baking soda, salt, flour) in large bowl. Add wets (buttermilk, eggs, water, oil, vanilla). Beat on medium speed of mixer for 2 minutes. The batter will be thin. Fill muffin tins 2/3 full with batter.

Bake: Bake 15 minutes or until toothpick comes out clean. Remove cupcakes from pan & cool completely. Frost with either the vanilla or chocolate frosting.

Chocolate frosting: In a medium bowl, melt 1 stick (0.5 cup) butter. Stir in 2/3 cup cocoa. Add 3 cups powdered sugar alternately with 1/3 cup milk & 1 teaspoon vanilla extract. Beat to spreading consistency.

Vanilla frosting: In a medium bowl, beat 0.5 stick (0.25 cup) butter, 0.25 cup shortening, and 2 tsp vanilla extract. Add 1 cup powdered sugar & beat until creamy. Then, add the remaining powdered sugar alternately with 3-4 tbsp milk. Beat to spreading consistency.