Preheat your oven to 160 C (320F) and line a muffin tin with cupcake baking cups.
Beat the butter and sugar in a stand mixer at a medium speed until light and fluffy. Add the eggs one at a time and beat until well incorporated. Make sure you scrape the bottom and sides while beating.
Add the sifted flour into the mixture and gently beat at a low speed until just combined. Make sure you scrape the sides and bottom while beating. Add the Baileys and beat at a low speed until just combined.
Divide the mixture evenly into your prepared baking cups. Bake for around 18 minutes or until a skewer comes out clean. Set aside and let cool before icing.
Using a stand mixer or beater, beat the butter at a medium speed until soft. Add the sifted icing a cup at a time and beat well with each addition. Make sure you scrape the sides and bottom while beating.
Add the Baileys and continue beating at a medium speed. If the icing is too soft, add a little more icing sugar.
Store in an airtight container for up to a day at room temperature and 5 days in the fridge.
Servings 0
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.