Heat your oven to 350 degrees, and line a cupcake pan with cupcake papers.

Combine all the cupcake ingredients in a mixing bowl, and stir until the batter is smooth. If you buy a chocolate cake mix that calls for different amounts of egg, or oil, or additional ingredients, follow those directions and replace the water for Irish Cream.

Fill the cupcake tin until ⅔ of the way full. Bake for 20-25 minutes until a toothpick inserted in the middle of the cupcakes comes out clean.

While the cupcakes bake, prepare the frosting. Place the butter in the bowl of an electric mixer and mix on medium speed for 2 minutes. This whips the butter, gets it creamy, and makes the frosting lighter and fluffier.

Add the vanilla and half of the Irish Cream and mix until evenly distributed. Then add the powdered sugar ½ cup at a time, stopping to scrape the sides of the bowl in between each addition. Once half of the powdered sugar has been added, add the remaining Irish Cream. Add the remaining powdered sugar ½ cup at a time. The result should be a light fluffy frosting that is easy to spread. You can add more Irish Cream to make the frosting more spreadable if necessary.

Once the cupcakes have finished baking, let them cool completely before adding the frosting. This is important because otherwise the heat from the cupcakes will melt the butter in the frosting, resulting in a gooey mess. I used a pastry bag to pipe the frosting onto the cupcakes, but a spoon or a knife work just fine too.

Sprinkle with heath bar bits if you like, then serve!