Preheat oven to 350 degrees F (175 degrees C). Line cupcake pan with liners.
Sift together the flour, baking powder, baking soda, cocoa and salt.
In a large bowl, cream together the butter and sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition.
Stir in vanilla extract.
Add the flour mixture alternately with the milk; beat well.
Fill each cupcake liner (2/3 full) and bake for 15 minutes or until a toothpick inserted comes out clean.