Preheat over to 325. Lightly spray Whoopie Pie Pan with nonstick cooking spray

In large mixing 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, baking powder and salt. Add half of the dry ingredients into the butter mixture and mix on low speed. When dry ingredients are almost incorporated, stop the mixer and add the milk. Continue to mix on low speed until all the ingredients are combined. Spoon 2 tablespoons of batter into each circle. Spread batter to the edges. Should be 2/3 full.

Bake for 11 - 13 minutes or until the top of the cake springs back when touched. Allow the cakes to cool in the pan for 8 minutes. Cool completely.

I chose to fill with vanilla icing and roll in heart shaped sprinkles for Valentines Day. Other fillings include jam or flavored cream cheese.