Frosted Chocolate Cupcake Tops

INGREDIENTS

For the cupcake tops:

1 3/4 cups

all-purpose flour

2 tbsp

unsweetened cocoa powder

1/2 tsp

baking soda

1/2 tsp

salt

1/2 tsp

espresso powder

2 oz

unsweetened chocolate, finely chopped

8 tbsp

unsalted butter, at room temperature

1 cup

sugar

large egg

1 tsp

vanilla extract

3/4 cup

buttermilk (or plain yogurt)

For the frosting:

1 cup

bittersweet chocolate chips

1/3 cup

plus 1 tbsp. sour cream (reduced fat is fine)

1 cup

confectioners’ sugar, sifted