01 - 
                Preheat your oven to 350°F (175°C) and line a muffin tin with cupcake liners.
              
              
              
                02 - 
                In a medium saucepan, melt the butter over low heat. Remove from heat and stir in the sugar until well combined.
              
              
              
                03 - 
                Beat in the eggs one at a time, then stir in the vanilla extract.
              
              
              
                04 - 
                In a separate bowl, whisk together the flour, cocoa powder, salt, and espresso powder. Gradually add this dry mixture to the wet ingredients, stirring until just combined.
              
              
              
                05 - 
                Stir in the milk until the batter is smooth.
              
              
              
                06 - 
                Divide the batter evenly among the prepared cupcake liners, filling each about 2/3 full.
              
              
              
                07 - 
                Bake for 18-20 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Allow the cupcakes to cool completely before frosting.
              
              
              
                08 - 
                Beat the softened butter in a large bowl until creamy. Gradually add the powdered sugar, beating until smooth. Mix in the dissolved espresso powder and 1 tablespoon of milk. Add more milk if needed to reach your desired consistency.
              
              
              
                09 - 
                Frost the cooled cupcakes with the coffee buttercream and enjoy.