First I whisked together the dry ingredients - 2c flour, 2 1/2 tbsp cocoa powder, 1/2 tsp baking powder and a pinch of salt.
I set that aside and creamed 1 stick of butter with 1c brown sugar then beat in an egg and 2tsp vanilla.
I didn't have buttermilk, so I mixed some lemon juice with 1/2 cup of regular milk and waited for it to curdle (sounds gross, but it works!). I added this and the dry ingredients into the wet mixture, then mixed in about 2 tbsp of red food coloring.
It made exactly 12 cakes - or enough for 6 Whoopies. At least, enough for 6 whoopies the way I poured them....