
Portion the batter onto the parchment-lined baking sheets in heaping spoonfuls; about 1 ½ tablespoons of batter each. Bake at 350 degrees F for 10-14 minutes, until the cakes are cooked through. Let cool on the pan.
As the cakes are cooling, prepare the filling. Combine the powdered sugar, dairy-free butter, dairy-free cream cheese, and vanilla in the bowl of a stand mixer (or a mixing bowl if using a hand mixer). Use the whisk attachment on low speed until combined, then turn speed to high and continue mixing until light and fluffy.
Nutrition analysis (approximate per whoopie pie): 415 calories, 19.5 g fat, 7 g saturated fat, 245 mg sodium, 58 g carbohydrate, 1 g fiber, 43 g sugar, 2.5 g protein, Vitamin D: 0%, Calcium: 3%, Iron: 7%, Potassium: 2%