Preheat your oven to 350°F (175°C) and line a 12-cup muffin tin with cupcake liners.

Cream together ½ cup unsalted butter and ¾ cup granulated sugar until light and fluffy, about 2-3 minutes.

Add 2 eggs one at a time, mixing well after each addition, followed by 1 teaspoon of vanilla extract and 1 tablespoon of instant espresso powder.

Slowly pour in ½ cup brewed espresso while mixing the batter until well incorporated.

Whisk together 1 cup all-purpose flour, ¼ cup unsweetened cocoa powder, 1 teaspoon baking powder, ½ teaspoon baking soda, and ¼ teaspoon salt in a separate bowl.

Gradually incorporate the dry ingredients into the wet ingredients, mixing on low speed until just combined.

Fill each cupcake liner about ⅔ full with batter and bake for 16-18 minutes.

Allow the cupcakes to cool in the pan for 5 minutes before transferring to a wire rack to cool completely.

Beat ½ cup unsalted butter until creamy, then gradually add 2½ cups powdered sugar, mixing well.

Blend in 1 tablespoon instant espresso powder and enough brewed espresso to achieve a fluffy consistency.

Frost each cooled cupcake with the espresso buttercream and garnish as desired.