Special equipment: a 2-inch (number 16) ice cream scoop
For the filling: In the bowl of a stand mixer fitted with the whisk attachment, add the confectioners' sugar, shortening, creme, vanilla, flour and milk. Whip together until fluffy, at least 10 minutes.
For the pies: Preheat the oven to 350 degrees F. Grease a baking sheet with butter. In the bowl of a stand mixer fitted with the paddle attachment, mix the butter, granulated sugar and shortening until fluffy, then add the eggs and vanilla.
In a large bowl, sift together the flour, baking soda and salt, then set aside. In a small bowl, combine the vinegar and the milk.
Add the milk mixture, cocoa and hot water to the bowl of the mixer, then add in the dry ingredients and mix until well blended.
Using a 2-inch (number 16) ice cream scoop, scoop large, rounded spoonfuls of batter 2 inches apart onto the prepared baking sheet. Bake for 9 to 11 minutes, then cool completely.
Using the same size ice cream scoop, scoop the filling and spread it between two of the shells like a sandwich. Wrap the whoopie pies in waxed paper or plastic wrap, then serve.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.