KAISER 12-Cup Whoopie Pie Baking Pan 38 x 27 cm Creativ Very Good Non-Stick Coating Short Baking Time for Sweet and Savoury Recipes. Classic whoopie pie! The only thing I changed was omitting the egg whites from the filling and adding about 2 Tb. of milk and an extra 1/4 cup of powdered sugar. Great recipe! The only thing I changed was omitting the egg whites from the filling and adding about 2 Tb. of milk and an extra 1/4 cup of powdered sugar.. The whoopie pie is the official state treat of Maine (not to be confused with the official state dessert, which is blueberry pie).  Gob [the term indigenous to the Pittsburgh region] has been trademarked by the Dutch Maid Bakery in Johnstown.. In a medium bowl, Beat together the butter, 100g sugar, 1/2 teaspoon salt and 1 tablespoon vanilla. Stir in the cooked milk mixture and beat for an additional 20 minutes, until really fluffy. Sandwich filling between two discs. ENJOY!!. This feature is not available right now. Please try again later.. Ingredients. Whoopie Pies: 1 2/3 cups all-purpose flour. 2/3 cup unsweetened cocoa powder. 1 1/2 teaspoon baking soda. 1/2 teaspoon salt. 4 tablespoons unsalted butter, room temperature.