1 box of brownies baked as directed on box. (9 x 13)
Bake and cool.
1/2 cup butter, softened
3 cups powdered sugar
1/4 cup cocoa
1/3 cup milk
1 teaspoon vanilla
Mix until smooth. It may be a but runny but will firm up in the fridge. Spread over top of peanut butter layer.
Chill until set up.
These do not have to be refrigerated, but they seem to taste better chilled.
They also seem to taste better the next day!!