• Preheat the oven to 350°F/180℃ and line a standard cupcake tin with cupcake liners.

Chocolate Cupcakes

• Sift together the flour, sugar, cocoa powder, baking soda, baking powder, and salt.
  ¾ cup all-purpose flour, ¾ cup granulated sugar, ⅓ cup dutch-processed cocoa powder, ¾ teaspoon baking soda, ½ teaspoon baking powder, ¼ teaspoon kosher salt
• In a separate bowl, mix together the egg, sour cream, vegetable oil, and vanilla with a whisk until combined.
  1 large egg, ⅓ cup sour cream, ⅓ cup vegetable oil, ½ teaspoon vanilla extract
• Add the wet ingredients to the dry ingredients and mix together with a wooden spoon or rubber spatula. Add the hot coffee and carefully stir to combine.
  ½ cup hot coffee or water
• Fill each cupcake liner ⅔ full, and bake for 13-15 minutes. The top of the cupcake will spring back when touched. A toothpick inserted into the center will come out clean with a few moist crumbs.
• Allow them to cool for 5 minutes in the pan, then use an offset spatula to remove them from the pan and transfer to a wire rack to cool completely.

Espresso Buttercream

• Cream the butter for 6 minutes in the bowl of a stand mixer with the paddle attachment or using an hand mixer.
  ½ cup unsalted butter
• Add the powdered sugar and mix on low speed until combined, then beat for 3 more minutes.
  2 cups powdered sugar
• Combine the espresso powder with a few drips of water and stir until until it becomes a slightly liquid paste. Add it to the creamed butter and sugar, along with the vanilla and mix to combine.
  1 tablespoon instant espresso or instant coffee, ½ tablespoon vanilla paste or extract
• Add the milk or heavy cream and mix on medium speed for another minute.
  2 tablespoons milk or heavy cream
• Transfer the buttercream to a piping bag and add to the tops of the cooled cupcakes.
• Top each cupcake with chocolate curls and chocolate covered coffee beans (optional).
  chocolate covered coffee beans, chocolate curls