Make your birthday sweets table that much sweeter with these Colorful Chocolate Whoopie Pies. A fun treat that kids and adults will like, these Colorful Chocolate Whoopie Pies are sure to be a party favorite!
Preheat oven to 350°F. Lightly spray Whoopie Pie Pan with nonstick cooking spray.
In large bowl, beat butter and sugar with electric mixer on medium speed until light and fluffy, about 3 minutes. Add egg and vanilla; beat until well combined.
In another bowl, sift together the flour, cocoa powder, baking powder, baking soda and salt. Add half the dry ingredients into the butter mixture and mix on low speed. When dry ingredients are almost incorporated, stop the mixer and add the buttermilk. Continue to mix on low speed until all ingredients are almost incorporated. Stop the mixer and add the remaining dry ingredients. Mix on low until just combined. Spoon 2 tablespoons of batter into each cavity; spread batter to the edges. Cavity should be about 2/3 full.
Bake for 8-10 minutes or until the top of the cake springs back when touched. Allow cakes to cool in pan 8 minutes. Remove from pan and cool completely before filling. To assemble pies spread filling on one cake and sandwich with another cake.