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Three authentic Irish Cupcakes beautifully arranged on a rustic wooden board, showcasing their moist chocolate texture and fluffy Baileys buttercream swirls.

The Ultimate Irish Cupcakes with Baileys Buttercream Frosting

The ultimate Irish Cupcakes recipe! Indulge in a rich, dark chocolate Guinness cupcake with a tender, moist crumb, topped with a generous swirl of creamy, fluffy Baileys Irish Cream buttercream frosting. Perfect for St. Patrick's Day!
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Prep Time 20 minutes
Cook Time 18 minutes
Total Time 38 minutes
Servings: 12 cupcakes
Course: Dessert
Cuisine: Irish-American
Calories: 485
Ingredients Equipment Method Notes

Ingredients
  

  • 1 cup (240ml) Guinness stout
  • 1 cup (120g) all-purpose flour
  • 3/4 cup (75g) Dutch-processed cocoa powder
  • 1 1/2 cups (300g) granulated sugar
  • 1/2 cup (120ml) vegetable oil
  • 2 large eggs room temperature
  • 1 1/2 tsp baking soda
  • 1/2 tsp salt
  • 1 cup (226g) unsalted butter softened to room temperature
  • 4 cups (480g) powdered sugar sifted
  • 1/3 cup (80ml) Baileys Irish Cream
  • 2 tbsp green and white sprinkles for garnish

Equipment

  • 1 12-cup muffin tin
  • 1 Electric Mixer (Stand or Handheld)
  • 1 Piping Bag with a Large Star Tip

Method
 

For the Dark Chocolate Guinness Cupcakes
  1. Preheat oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners.
  2. In a large bowl, whisk together flour, cocoa powder, sugar, baking soda, and salt. In a separate bowl, combine the Guinness, oil, and eggs.
  3. Pour the wet ingredients into the dry ingredients and whisk until just combined. The batter will be thin. Do not overmix.
  4. Fill cupcake liners two-thirds full. Bake for 16-18 minutes, or until a toothpick inserted into the center comes out with moist crumbs attached.
  5. Let cool in the tin for 5 minutes before transferring to a wire rack to cool completely.
For the Creamy Baileys Buttercream
  1. In a large bowl using an electric mixer, beat the softened butter on medium-high speed until pale and fluffy, about 3-4 minutes.
  2. Reduce speed to low and gradually add the sifted powdered sugar until combined. Increase speed to medium-high and beat until smooth, about 2 minutes.
  3. With the mixer on low, slowly pour in the Baileys Irish Cream. Once incorporated, increase speed to high and whip for 1 minute until light and fluffy.
  4. Transfer frosting to a piping bag fitted with a large star tip. Pipe a generous swirl onto each completely cooled cupcake. Top with green and white sprinkles.

Notes

Room Temperature is Non-Negotiable: For a smooth, emulsified batter and frosting, ensure your eggs and butter are at room temperature.
Don't Overmix the Batter: Overmixing develops gluten, which can lead to tough cupcakes. Mix only until the flour streaks disappear.
Cool Completely Before Frosting: Even slightly warm cupcakes will cause the butter in the frosting to melt, resulting in a soupy mess. Patience is key!
Sift Your Powdered Sugar: For the smoothest, most velvety buttercream, always sift your powdered sugar to remove any clumps.