Chocolate cupcakes

These are from Martha Stewart and have become my standard birthday cake or cupcake.
Makes 24
3/4 cup unsweetened cocoa powder
1 1/2 cups flour
1 1/2 cups sugar
1 1/2 tsp. baking soda
3/4 tsp. baking powder
3/4 tsp. salt
2 eggs
3/4 cup warm water
3/4 cup buttermilk
3 Tbsp. oil
1 tsp. vanilla

Preheat oven to 350 F. Line muffin tins with paper liners. Sift cocoa powder, flour, sugar, baking soda, baking powder, and salt into a large bowl. Add eggs, warm water, buttermilk, oil, and vanilla, and mix until smooth.

Divide batter among muffin cups, filling each 2/3 full. Bake until tops spring back when touched, about 20 minutes. Transfer cupcakes to wire racks and let cool. Cupcakes will keep, covered, for up to 3 days. They freeze beautifully.

These are frosted with basic buttercream.