• Preheat your oven to 350°F, or 400°F if you want cupcakes with a higher dome. With the 400°F option, you will reduce the oven temperature to 350°F after the first 7 to 9 minutes of baking.
• Line a pair of 12-count muffin pans with cupcake liners.

Prepare the Cupcake Batter

• In a large mixing bowl, whisk together the all-purpose flour, cocoa powder, sugar, baking powder, baking soda, and salt until the dry ingredients are well combined.
• In another mixing bowl, whisk together the vegetable oil, eggs and vanilla extract until smooth.
• Then add the buttermilk and mix again until combined.
• Pour the wet mixture into the bowl containing the dry ingredients.
• Using a hand or stand mixer on low speed, mix just until combined.
• Slowly pour in the hot coffee while mixing on low until the batter is smooth. Scrape down the sides and bottom of the mixing bowl to ensure you have combined all of the ingredients. The batter will be thin.
• Fill each cupcake liner about ⅔ full. You may have extra batter. Either discard it or make a few extra cupcakes.

Bake the Cupcakes

• For cupcakes with a taller dome, bake at 400°F for 7 to 9 minutes, then reduce the oven temperature to 350°F for the remaining time without opening the oven door. If you prefer to bake at 350°F the whole time, that works too, but the tops will be flatter.
• Bake until a toothpick inserted in the center comes out clean or with a few moist crumbs, 15 to 20 minutes total.
• Remove from the oven and let cupcakes cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely before frosting.

Prepare the Frosting

• Beat the unsalted butter on medium-high speed until creamy, about 2 minutes. Reduce the speed to low and slowly add powdered sugar, heavy cream, vanilla extract, and a pinch of kosher salt.
• Beat on high for 3 to 4 minutes until light and fluffy.
• If the frosting is too thick, add more heavy cream a tablespoon at a time until it reaches a smooth, pipeable consistency. If it’s too thin, add more powdered sugar, a few tablespoons at a time, until it holds its shape.
• Once your buttercream is ready, scoop out about ¾ of it for the red frosting and leave about ¼ for the white. You can weigh it on a kitchen scale if you want to be exact, but just eyeballing the amounts works fine too.
• To tint the larger portion, add red gel coloring in small amounts, mixing thoroughly each time. Red takes a generous amount, so continue building the color until you reach a deep, vibrant shade, then cover and let it rest so the color can deepen.
• Leave the smaller portion plain for the trim and pom poms, or you can brighten it with the tip of a toothpick dipped in purple gel food color to cancel out any yellow tones.

Frost the Cupcakes

• Fit a large piping bag with a round tip and fill it with the red frosting.
• Pipe a tall swirl in the shape of a Santa hat on each cupcake.
• Use another piping bag fitted with a small star tip for the white frosting and pipe a border around the base of the red hat.
• Add a small dollop on top for the pom-pom.