8 Tbsp (1 stick, 4 ounces) unsalted butter
1/2 cup Dutch processed cocoa
2 ounces bittersweet chocolate, chopped
3/4 cup flour
3/4 teaspoon baking powder
1/2 teaspoon baking soda
2 large eggs
1/2 teaspoon salt
3/4 cup sugar
1 1/2 teaspoons mint extract
1/2 cup sour cream
8 Tbsp butter, room temperature (1 stick, 4 ounces)
1 Tbsp milk
1/4 to 1/2 teaspoon peppermint extract
2 cups powdered sugar
4 ounces cream cheese, room temperature
4 Tbps butter, room temperature (1/2 stick, 2 ounces)
1/4 to 1/2 teaspoon peppermint extract
1 1/2 cups powdered sugar (confectioner's sugar)
Fresh mint for garnish