For the spiced chocolate cupcakes:
For the eggnog buttercream:
To make the cupcakes:
Preheat oven to 350°F. Line a muffin pan with cupcake liners or grease and flour.
In a small bowl, whisk together the hot coffee and cocoa powder until smooth and no lumps remain. Set aside to cool slightly.
In another bowl, sift together the flour, salt, baking soda, cinnamon, and cloves.
In the bowl of a stand mixer fitted with a paddle attachment, beat the egg, egg yolk, and sugar on medium high speed until pale yellow in color. Add the sour cream and mix until combined, followed by the vegetable oil. Add the flour mixture all at once and mix until combined. Add the cocoa mixture and mix until smooth, scraping down the sides of the bowl as needed.
Fill the cupcake liners ⅔ full with the batter and bake until a toothpick inserted into the center of a cupcake comes out clean, 12-15 minutes. Let cupcakes cool in the pan for a few minutes, then turn out onto a wire rack to cool completely.
To make the buttercream:
In the bowl of a stand mixer fitted with a paddle attachment, beat together the butter, powdered sugar, salt, nutmeg, vanilla, and bourbon (if using).
Add the eggnog a tablespoon at a time while mixing on medium high speed until desired consistency is reached. Increase speed to high and beat for a few minutes until smooth.
Frost cupcakes with the buttercream. The cupcakes should be stored in an airtight container and will keep at room temperature for several days and about a week in the fridge.
Calories: 348kcal, Carbohydrates: 46g, Protein: 2g, Fat: 19g, Saturated Fat: 13g, Cholesterol: 51mg, Sodium: 218mg, Potassium: 67mg, Fiber: 1g, Sugar: 38g, Vitamin A: 386IU, Vitamin C: 1mg, Calcium: 20mg, Iron: 1mg