Preheat the oven to 350°F (175°C) and grease or line a muffin tin.
In a bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt.
In another bowl, mix sugar, brewed coffee, milk, vegetable oil, egg, and vanilla extract.
Add wet ingredients to dry ingredients and stir until combined.
Divide batter evenly among muffin cups, filling each 2/3 full.
Bake for 18-20 minutes, or until a toothpick comes out clean.
Allow cupcakes to cool before serving.