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A close-up shot of a St Patricks Day cupcake cut open to reveal a glossy dark chocolate ganache filling inside its moist Guinness chocolate cake base.

Ultimate St. Patrick's Day Cupcakes (Guinness, Baileys & Jameson)

The ultimate St. Patrick's Day dessert featuring a rich Guinness chocolate cupcake, a surprise Jameson whiskey ganache filling, and a fluffy Baileys Irish Cream buttercream. A decadent and festive treat for adults.
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Prep Time 30 minutes
Cook Time 22 minutes
Total Time 52 minutes
Servings: 12 cupcakes
Course: Dessert
Cuisine: American, Irish
Ingredients Equipment Method Notes

Ingredients
  

For the Guinness Chocolate Cupcakes
  • 1 ¾ cups All-Purpose Flour (210g)
  • ¾ cup Dutch-Processed Cocoa Powder (75g)
  • 1 ½ cups Granulated Sugar (300g)
  • 2 tsp Baking Soda (10g)
  • ¾ tsp Salt (4g)
  • ½ cup Vegetable Oil (120ml)
  • 2 large Eggs, at room temperature
  • 1 cup Guinness Stout (240ml)
  • ½ cup Buttermilk, at room temperature (120ml)
  • 1 tsp Vanilla Extract (5ml)
For the Jameson Whiskey Ganache Filling
  • 4 oz Dark Chocolate, finely chopped (115g)
  • ½ cup Heavy Cream (120ml)
  • 1 tbsp Unsalted Butter (15g)
  • 1 tbsp Jameson Irish Whiskey (15ml)
For the Baileys Buttercream Frosting
  • 1 cup Unsalted Butter, softened (226g)
  • 4 cups Powdered Sugar, sifted (480g)
  • ¼ cup Baileys Irish Cream (60ml)
  • 1-2 tbsp Heavy Cream or Milk (15-30ml), as needed
  • ⅛ tsp Salt (1g)
For Assembly & Garnish
  • 2 tbsp Dark Chocolate Syrup (30ml), for drizzling
  • 1 tbsp Green Sugar Crystal Sprinkles (15g)

Equipment

  • 1 Muffin Tin
  • 1 Piping Bag with Star Tip
  • 1 Electric mixer
  • Mixing bowls

Method
 

Part 1: Make the Guinness Chocolate Cupcakes
  1. Preheat your oven to 350°F (175°C). Line a 12-cup muffin tin with brown paper liners.
  2. In a large bowl, whisk together the all-purpose flour, Dutch-processed cocoa powder, granulated sugar, baking soda, and salt.
  3. In a separate medium bowl, whisk the vegetable oil, room-temperature eggs, Guinness, buttermilk, and vanilla extract until fully combined.
  4. Pour the wet ingredients into the dry ingredients. Whisk gently until just combined. Do not overmix.
  5. Divide the batter evenly among the 12 cupcake liners, filling each about two-thirds full. Bake for 18-22 minutes, or until a wooden toothpick inserted into the center comes out with a few moist crumbs attached.
  6. Let the cupcakes cool in the pan for 5 minutes before transferring them to a wire rack to cool completely before filling or frosting.
Part 2: Prepare the Jameson Ganache Filling
  1. Place the finely chopped dark chocolate in a heatproof bowl. Heat the heavy cream in a small saucepan over medium heat until it just begins to simmer.
  2. Pour the hot cream over the chopped chocolate and let it sit undisturbed for 5 minutes.
  3. Add the butter and Jameson whiskey. Whisk slowly until the ganache is smooth, dark, and glossy.
  4. Let the ganache cool until it has a thick but still pipeable consistency.
Part 3: Whip the Baileys Buttercream
  1. In a large bowl, beat the softened unsalted butter on medium-high speed for 3-4 minutes until very pale and fluffy.
  2. Reduce mixer speed to low and gradually add the sifted powdered sugar, alternating with the Baileys Irish Cream.
  3. Once incorporated, add the salt and increase speed to medium-high, whipping for another 3-5 minutes until light and fluffy. Add heavy cream as needed to adjust consistency.
Part 4: Assemble Your Masterpieces
  1. Once completely cool, use a cupcake corer or small knife to remove the center from each cupcake.
  2. Fill the core of each cupcake with the cooled Jameson ganache.
  3. Use a piping bag with a star tip to pipe a tall swirl of Baileys buttercream on top of each cupcake.
  4. Drizzle with dark chocolate syrup and finish with a sprinkle of green sugar crystals. Serve immediately.

Notes

Room Temperature is Key: For the smoothest batter and fluffiest frosting, ensure your eggs, buttermilk, and butter are all at room temperature before you begin.
Don't Overfill the Liners: Filling the cupcake liners only two-thirds full prevents them from overflowing and ensures a clean base for your frosting.
Sift Your Dry Ingredients: This is a non-negotiable step to guarantee a lump-free, silky smooth texture in both your cake and frosting.
Cooling is Crucial: Be patient and let the cupcakes cool completely to room temperature, otherwise, your beautiful buttercream will melt.