INGREDIENTS
1 cup
all-purpose flour
1/2 cup
unsweetened Dutch-process cocoa powder
1 cup
granulated sugar
3/4 tsp
baking soda
1/2 tsp
baking powder
1/2 tsp
salt
1
egg plus 1 yolk, lightly beaten
2 tbsp
unsalted butter, melted and cooled
1/2 cup
buttermilk
1/2 tsp
pure vanilla extract
24
cream-filled chocolate sandwich cookies, plus more, finely crushed, for sprinkling
Cookies and Cream Buttercream