Gather the cupcake ingredients - * Guinness stout beer * Vegetable oil * Milk * Eggs * Vanilla extract * Sugar * Flour * Baking powder * Cocoa powder
– Place the Guinness in a small saucepan set over medium-low heat. Bring the mixture to a simmer and cook it until it has reduced to about 1/2 cup. This should take 15-20 minutes. Once the Guinness has reduced, set it aside to cool. – In a large bowl, whisk together the vegetable oil, milk, eggs, and vanilla. Then, whisk in 1/4 cup of the cooled reduced Guinness. Next, add the sugar and whisk to combine.
Add the flour, cocoa, and baking powder. Whisk just until no large lumps remain.
Divide the batter between the cupcake tins, filling each one 3/4 of the way full.
Bake for 16-18 minutes or until a toothpick inserted into the center comes out clean. Remove the cupcakes to a wire rack and cool completely before icing.
Gather the frosting ingredients - * Powdered sugar * Semi-sweet chocolate * Vanilla extract * Reduced Guinness * Butter
– Add the softened butter and melted chocolate to the bowl of a stand mixer. Beat until combined. – Slowly add the powdered sugar before adding the reduced Guinness and vanilla extract. – Turn the mixer to medium-high speed and beat until the buttercream becomes light and fluffy.
– Transfer to a piping bag fitted with your choice of tip. – To assemble, poke the top of each cupcake 5 times with a fork and pour over 1 teaspoon of the Guinness syrup. – Pipe the frosting on top of each cupcake and garnish with chocolate shavings or sprinkles.
Enjoy immediately and store any leftover cupcakes in the fridge for up to three days.