Preheat oven to 350 °F. Line 2 cupcake pans with cupcake papers or spray with non-stick cooking spray.
Combine all ingredients in the bowl of an electric stand mixer. Blend until combined.
Fill cupcake papers 3/4 full.
Bake 19-23 minutes, turning pans halfway through. Cool completely on a cooling rack.
Frosting
Put the white chocolate chips in a glass measuring cup or glass bowl, and add heavy cream. Microwave at 50% power for 30-second intervals, stirring after each cycle. Stir until smooth.
In the bowl of an electric stand mixer, fitted with the paddle attachment, combine powdered sugar, butter, Irish Cream liquor, and melted chocolate. Mix to combine. Add additional Irish Cream liquor or cream until the frosting is the right consistency for spreading.
This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.