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! B. Recipe by: . L.D. 71, officially known as "An Act to Designate the Whoopie Pie as the State Dessert", read "The whoopie pie, a baked good made of two chocolate cakes with a creamy frosting between them, is the official state dessert".. Heat oven to 180C/160C fan/gas 4 and line baking trays with parchment. Mix flour, cocoa, bicarb, sugar and a pinch of salt. Whisk the egg, oil and buttermilk together, then mix into dry ingredients with 75ml boiling water.. Beat the butter and sugar in an electric mixer on high speed until light and fluffy. Beat in the egg, followed by the vanilla and buttermilk. Reduce speed to low, add dry ingredients and beat until combined.. . .