Preheat oven to 350 degrees. Prepare muffin tins with cupcake liners.
Sift together flour, baking powder, baking soda, cocoa, and salt. Set aside.
In a large bowl, cream together the butter and sugar until light and fluffy. Add the eggs one at a time, beating well with each addition. Add vanilla. Combine. Add flour mixture alternately with the milk, mix well. Fill the muffin cups 3/4 full.