Peppermint Mocha Cupcakes

A quick post before I run out the door, because I've been horribly behind on posting lately. I'm not completely happy with the cupcake portion of this (although it is good, I'm just a perfectionist), but the frosting is spot-on. I scaled the recipe in half, otherwise the one below makes 2 dozen.

Peppermint Mocha Cupcakes (from Tracey's Culinary Adventures, originally Annie's Eats)

Ingredients
Cupcakes
2 2/3 cups all-purpose flour
2/3 cup unsweetened cocoa powder
2 1/2 teaspoons espresso powder
2 teaspoons baking powder
1 teaspoon baking soda
1/2 teaspoon salt
1 cup milk, at room temperature
1 cup strong brewed coffee, at room temperature
1 teaspoon peppermint extract
1 cup unsalted butter, at room temperature
1 cup granulated sugar
1 cup light brown sugar
2 large eggs, at room temperature

1. Preheat oven to 350 F. Line two cupcake pans with paper liners.
2. In a medium bowl, whisk together the flour, cocoa powder, espresso powder, baking powder, baking soda and salt.
3. Combine the milk, coffee and peppermint extract in a small bowl.
4. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugars on medium-high speed until light and fluffy, about 3-4 minutes. Scrape down the sides of the bowl as needed.
5. Add the eggs to the bowl, one at a time, letting the first incorporate fully before adding the second.
6. With the mixer on low speed, alternately add the dry and wet ingredients, starting and ending with the dry ingredients. Mix only until everything is incorporated.
7. Divide the batter evenly between the prepared cupcake liners. Bake for 18-20 minutes, or until a toothpick inserted in the center comes out clean. Let the cupcakes cool in the pan for about 5 minutes, then transfer them to a wire rack to cool completely.

Frosting
6 large egg whites
1 3/4 plus 2 tablespoons granulated sugar
1 1/2 cups unsalted butter, at room temperature
3 teaspoons peppermint extract
1 teaspoon vanilla extract
food colouring (if desired)

1. In a heatproof bowl (ideally your stand mixer bowl), stir the egg whites and sugar together.
2. Set the bowl over a pan of simmering water. Heat, whisking frequently, until the mixture reaches 160 F and the sugar has dissolved.
3. Fit your mixer with the whisk attachment. Beat the egg whites and sugar on medium-high speed until stiff peaks form and the mixture has cooled to room temperature, about 8-10 minutes.
4. Reduce the mixer speed to medium and add the butter, 2 tablespoons at a time, adding more once each addition has been incorporated. If the frosting looks soupy or curdled, continue to beat on medium-high speed until smooth again, about 3-5 minutes more.
5. Stir in the peppermint and vanilla extracts (and food colouring if desired) and mix just until incorporated.