For the batter and a 24 cm-in-diameter springform pan: 320 g of all-purpose flour 90 g of cocoa powder 250 g of sugar 150 g of butter 150 g of sour cream 2 large eggs 230 ml of milk 1 tsp of . Ever heard of a whoopie pie? They're a bit like a macaroon but with a more cake-like texture. Hugely popular Stateside, the name comes from when Amish women would put them in farmers' lunchboxes and they'd supposedly shout 'whoopie' if they found one in their box!. A few years before the whoopie pie became Maine’s official treat, the Maine Whoopie Pie Festival was established by the Center Theatre in the small rural town of Dover-Foxcroft.. 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!. 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.. whoopie pie (plural whoopie pies) A baked good consisting of two round , mound - shaped pieces of cake (typically chocolate cake ) with a sweet , creamy filling or frosting sandwiched in between..