Preheat the oven to 350 degrees and line a 12-count muffin pan with cupcake liners. Set aside.
In a medium-sized bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt.
In a large bowl, whisk together the milk, oil, warm water, egg, and vanilla extract.
Add the flour mixture to the wet ingredients and whisk just until combined (the batter will be thin).
Fill the cupcake liners a little more than ½ way full (exactly 3 tablespoons) and bake for 16-20 minutes, or until a toothpick inserted into the middle of the cupcake comes out clean.
Allow them to cool in the pan for 10 minutes and then transfer them over to a wire rack to finish cooling.
Top each cupcake with your favorite frosting, like this chocolate cream cheese frosting or chocolate buttercream. Use a piping bag and frosting tip to frost the cupcakes.
