The Wilton Nonstick 12-Cavity Whoopie Pie Pans should be filled with 1/8 cup (2 Tbsp) of batter per shell, and the 24-cavity mini pans take half that much batter. So you may get fewer, or more, than 36 filled pies out of this recipe Also, although they freeze beautifully, if you don't want to bake that many, you can cut the recipe in half.. Fall in love with this easy recipe for whoopie pies. Two light discs of chocolate sponge sandwich a fluffy vanilla buttercream filling. Perfect for cake sales, packed lunch treats or making friends at the office!. The batter will spread just a bit as it cooks, and your whoopie pies will end of being about 2 1/2 inches in diameter. You’ll have about 18 tasty little cakes. You’ll have about 18 tasty little cakes.. Whoopie Pies are easy to make and very versatile, simply a pair of small sponge cakes glued together with a filling and, if desired, topping. Read More This entry was posted in Recipes , Sweet Recipes , Equipment and tagged whoopie pie , whoopie pies , dark chocolate , sponge cakes on 05/11/2010 by Patrick .. . .