Preheat oven to 400 degrees. Line 12 standard muffin cups with paper liners.
Whisk together flour, baking powder, salt and cocoa in a large bowl. In a small bowl, combine butter, sugar and egg. Add milk and vanilla and stir to incorporate. Combine wet and dry ingredients and stir to moisten. Fold in the two types of chocolate chips. Do not over mix. Bake for 15 to 18 minutes.