For the Cupcake:
1/2 cup butter, softened
1 1/2 cup sugar
2 eggs
1 1/2 cup flour
1/2 cup unsweetened dark cocoa powder
1/2 tsp kosher salt
1 tsp baking soda
2 Tbsp espresso powder
1/2 tsp baking powder
1/2 cup brewed coffee, cooled
1/2 cup buttermilk

For the Frosting:
1/2 cup butter, softened
4 oz cream cheese, softened
1 Tbsp espresso powder
1/4 cup heavy cream
1 Tbsp chocolate syrup
5 cup powdered sugar