Preheat the oven to 350 degrees.
Line 16 cupcake molds with paper liners, set aside.
Using stand mixer fitted with the whisk attachment or a hand mixer on low, mix the melted butter, eggs, beer and vanilla extract until combined.
In a separate bowl, whisk together the dry ingredients (flour, cocoa powder, sugar, salt & baking powder).
Add dry ingredients to wet ingredients in 4 parts, mixing on low-medium after each addition.
Using a cookie dough scoop or a spoon, fill each cupcake tin with batter. Fill to 3/4 full.
Bake for 20-25 minutes or until a toothpick comes out clean.
Remove from oven and allow them to cool completely on a wire rack or cutting board.