To prepare a stefs whoopie pies with peanut butter frosting recipe, first you need to prepare the filling. First, you'll need 2 cups rolled oats, 1 cup shredded coconut, and 1 teaspoon vanilla extract. Then, mix the dry ingredients together until they're well combined. Next, add the wet ingredients and mix until the ingredients are well blended. Finally, pour the mixture into the prepared pie shell and bake the pie for 20 to 25 minutes or until it's golden brown.