Cook cookies for 9 minutes. Remove them from the oven, let them cool for one minute and then move them to a cooling rack. Once completely cooled, spoon frosting onto the back of one cookie and then top it off back to back with a cookie of the opposite color, making a 4th of July Cake Mix Whoopie Pie.. 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".. 496 results for whoopie pie Save whoopie pie to get e-mail alerts and updates on your eBay Feed. Unfollow whoopie pie to stop getting updates on your eBay feed.. 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!. Fourth of July mini whoopie pies. Normally whoopie pies are piped onto a nonstick baking mat. I made them by putting red and blue cake mix batter into a mini muffin tin and baking at 350 degrees . 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..