Yield: 12 cupcakes

1-1/3 all-purpose flour
1/3 cup unsweetened cocoa powder
1 teaspoon baking powder
½ teaspoon baking soda
¼ teaspoon salt
½ cup whole milk
½ cup strong brewed coffee
1½ teaspoons espresso powder
1 teaspoon vanilla extract
½ cup (1 stick) unsalted butter, at room temperature
½ cup granulated sugar
½ cup light brown sugar
1 egg, at room temperature

Espresso Buttercream Frosting:
(Makes enough to frost 12 cupcakes)

1 cup (2 sticks) unsalted butter, at room temperature
2½ cups powdered sugar
1½ teaspoons vanilla extract
1½ teaspoons espresso powder