For the Chocolate Whoopie Pies: 1/2 cup vegetable oil 1/2 cup brown sugar (packed) 1/2 cup granulated white sugar 1 egg 1 tsp vanilla extract 1/2 cup whole milk 2 1/4 cups all purpose flour (spooned and leveled) 1/2 cup cocoa powder 1 tsp baking soda 1 tsp baking powder 1/2 tsp salt 1/4 cup hot water (the hottest water from the sink is okay) For the Buttercream: 1 1/2 cups unsalted butter 5-6 cups powdered sugar 3 TBS heavy cream 1 1/2 tsp vanilla extract 1 dash salt 1 cup Halloween sprinkles
Use a medium cookie scoop (it should be 1 1/2 TBS in size) to scoop the cookie batter onto the cookie sheets. This will keep your hands clean of the very sticky batter, and helps to keep the cookies more uniform in their size. Match similar sized and shaped cookies with each other for the sandwiches. Some of them will spread differently, or more oval shaped, and the cookies line up better when the top and bottom match better.