For the cupcake:
- 1 1/2 sticks unsalted butter, at room temperature
- 2/3 cup granulated sugar
- 2/3 cup light brown sugar, packed
- 2 eggs, at room temperature
- 2 teaspoons pure vanilla extract
- 1/2 cup milk, at room temperature
- 1/2 cup brewed strong coffee
- 1/2 cup sour cream, at room temperature
- 1 3/4 cups all-purpose flour
- 1/3 cup cocoa powder
- 1/3 cup espresso powder
- 1/3 cup instant espresso
- 1 1/2 teaspoons baking soda
- 1/2 teaspoon kosher salt
For the espresso cream filling:
- 2 cups heavy whipping cream
- 3 tablespoons (or to taste) strong espresso, at room temperature
For the caramel buttercream frosting:
- 2 sticks unsalted butter, at room temperature
- 3 1/2 cups powdered sugar
- 1 teaspoon milk
- 1 teaspoon caramel extract (or 3-5 drops of caramel flavoring)
1/8 teaspoon salt
- caramel sauce for drizzle
- Preheat the oven to 350 degrees F.
- Using an electric mixer, cream the butter and two sugars on high speed until light and fluffy.
- Lower the speed to medium, and add the eggs one at a time.
- Lower the speed to low, and add vanilla. Mix until combined.
- Scrape down the sides of the bowl with a spatula to make sure all of the ingredients are incorporated.
- In a separate bowl, whisk together the milk, sour cream, and brewed coffee.
- In another bowl, sift together the flour, cocoa powder, espresso powder, instant espresso, baking soda, and salt.
- On low speed, add the milk mixture and flour mixture alternately in thirds to the butter mixture. Start with the milk mixture and end with the flour mixture. Mix until just combined.
- Again, scrape down the sides of the bowl with a spatula to make sure all of the ingredients are incorporated.
- Line cupcake pans with paper wrappers and fill each cup about 2/3 full.
- Bake on the middle rack of the oven for 17-20 minutes.
- Test the cupcakes with a toothpick – insert a toothpick through the center of a cupcake. If it comes out clean, the cupcakes are done. If not, leave the cupcakes in the oven for another minute and then test the cupcakes again.
- Cool cupcakes in the pan for 10 minutes.
- Remove cupcakes from the pan and cool completely.
- Using a cupcake corer (I used the Cuisipro Cupcake Corer), hollow out a hole in the center of each cupcake. To do this, twist the corer into the cupcake and then slowly remove it. Push the plunger down to remove the cake from the corer.
- For the filling: using an electric mixer, whisk the heavy whipping cream on high speed until soft peaks form. Add the espresso and continue to whisk on high speed until stiff peaks form.
- Put the whipped cream into a piping bag and place in the refrigerator until ready to fill cupcakes.
- For the frosting: using an electric mixer, mix the butter, powdered sugar, milk, caramel extract (or flavoring), and salt together until completely smooth.
- Put the frosting in a piping bag.
- Fill each cupcake with the espresso cream.
- Frost each cupcake.
- Drizzle caramel over the frosting.