Step 1

In a small saucepan, bring the Guinness to a boil over medium-high heat. Once boiling, reduce to medium heat and allow to simmer until reduced down to 2/3 cup, about 20 minutes. Set 1/2 cup aside to cool for 10-15 minutes before using in the cupcake batter. While it’s warm, mix the rest of the reduced Guinness (about 2-2.5 Tablespoons) with the 2 teaspoons of espresso powder used in the frosting. Set this mixture aside for step You can do this step 1 day ahead of time if needed. Refrigerate overnight. Bring reduced beer to room temperature before using in both the cupcake batter and frosting.

Step 2

Preheat the oven to 350°F (177°C). Line a 12-cup muffin pan with cupcake liners. Line a second pan with 4 liners – this recipe makes about 16 cupcakes. Set aside.

Step 3

Whisk the flour, cocoa powder, espresso powder, baking soda, and salt together in a large bowl until thoroughly combined. Set aside. In a medium bowl, whisk the oil, brown sugar, eggs, sour cream, and vanilla together until completely smooth. Pour the wet ingredients into the dry ingredients, add the 1/2 cup (120ml) reduced Guinness, then whisk until *just* combined. Do not over-mix. The batter will be on the thinner side.

Step 4

Pour or spoon the batter into the liners. Fill each 2/3 full to avoid spilling over the sides or sinking. Bake for 19-22 minutes, or until a toothpick inserted in the center comes out clean. Don’t over-bake, which will dry out the cupcakes. Begin checking for doneness at 19 minutes. For around 36 mini cupcakes, bake for about 11-13 minutes, same oven temperature. Allow the cupcakes to cool completely before frosting.

Step 5

Have the Guinness/espresso powder mixture from step 1 handy. In a large bowl using a handheld or stand mixer fitted with a whisk attachment, beat the butter on high speed until completely smooth and creamy, about 2-3 minutes. Add the confectioners’ sugar, cocoa powder, milk, reduced Guinness/espresso powder mixture, milk, and vanilla extract. Beat on low for 30 seconds then increase to high speed and beat until combined and creamy. Taste. Add a pinch of salt if desired. (I always add 1/8 teaspoon.) If you want the frosting a little thicker, add 1/4 cup (30g) of confectioners’ sugar.

Step 6

Frost cooled cupcakes. I piped a basic tall swirl using Ateco 849 piping tip.

Step 7

Leftover cupcakes keep well covered tightly in the refrigerator for 3 days.