Preheat the oven to 180°C (356°F).
In a bowl, combine flour, cocoa powder, baking powder, and salt.
In another bowl, cream together the butter and sugar.
Add the eggs one at a time and mix well.
Add the milk and vanilla extract and mix.
Sift the dry ingredients into the mixture and blend evenly.
Gently fold in chocolate chips.
Divide the batter into muffin cups.
Bake in the preheated oven for 20–25 minutes.