Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.
In a medium-sized mixing bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt.
In a separate large mixing bowl, cream the butter and sugar together until light and fluffy.
Add the eggs and vanilla extract to the butter mixture and mix until combined.
Gradually add the dry ingredients to the wet mixture, alternating with the milk, and mix until well combined.
Fill the muffin cups about 3/4 of the way full with the batter.
Bake for 18-20 minutes, or until a toothpick inserted in the center comes out clean.
Allow the cupcakes to cool for a few minutes in the tin, then transfer them to a wire rack to cool completely, about 30 minutes.