Preheat oven to 350 degrees. Place 16 cupcake liners in a muffin tin and set aside.

In the bowl of a stand mixer (or large bowl), cream butter and brown sugar. Slowly mix in the eggs until blended; set aside.

In another bowl mix together flour, cocoa, baking soda, baking powder, and salt. Slowly add to the creamed mixture, alternating with beer until well blended. [Add a splash or 2 of beer if dough is too thick.]

Pour batter to fill each muffin cup about 2/3 of the way. Bake for 15-18 minutes.

Let cool in pan for 5 minutes and then remove to cool completely on a cooling rack.

Irish Frosting:

In a stand mixer (or with hand mixer), cream butter and sugar until it is light and fluffy. Add a little Irish cream, mixing well, until you achieve the consistency you prefer. Set aside (or put in fridge until ready to frost cupcakes.)

Frost cupcakes when they are completely cool. Serve!