Preheat oven to 350°F.
Line your muffin pans with cupcake liners and set aside.
In a large bowl, add together the flour, cocoa powder, baking powder, baking soda, and salt, sift to combine.
Add in the sugar and brown sugar stir until combined.
Add the oil, buttermilk, egg, cream beer, and vanilla extract. Stir until combined.
Pour the batter 3/4 in the cupcake liners.
Fill each one 3/4 of the way full.
Bake at 350°F for 17-20 minutes.
Remove the cupcakes from the oven.
Transfer the cupcakes to a wire rack to cool