01 - 
                Turn your oven to 350°F (175°C) and get a muffin pan ready with cupcake liners.
              
              
              
                02 - 
                Warm butter on low heat in a medium pot until melted. Remove from heat and mix in sugar until it’s smooth.
              
              
              
                03 - 
                One at a time, beat the eggs in. Then mix in the vanilla extract.
              
              
              
                04 - 
                In another bowl, toss together the flour, espresso powder, cocoa powder, and salt. Gradually fold this into the wet mixture until just blended.
              
              
              
                05 - 
                Mix in milk until everything feels smooth and fully combined.
              
              
              
                06 - 
                Spoon the batter into the cupcake liners, filling them about two-thirds full.
              
              
              
                07 - 
                Pop the pan into the oven for 18-20 minutes. Check by sticking a toothpick in—a clean one means they’re done. Let the cupcakes cool down before you frost them.
              
              
              
                08 - 
                Whip the softened butter in a bowl until it’s fluffy. Gradually add powdered sugar while beating, then mix in the espresso mixture and 1 tablespoon of milk. If it’s too thick, splash in another tablespoon of milk.
              
              
              
                09 - 
                Spread the coffee buttercream over the cooled cupcakes and dig in.