Preheat oven to 425 degrees F. Spray Whoopie Pie pan well with cooking spray.
In a large, nonstick skillet, over medium heat, melt butter. Stir in chopped apples, sugar, cinnamon and nutmeg. Saute until apples are softened, about 10 minutes. Set aside.
In a small bowl, mix together all ingredients for the crumble and set aside.
Unroll pie crusts on a cutting board. Using a 4-inch round cookie cutter (not smaller), cut out 12 circles from the dough. (You are going to extra dough scraps so plan to make some pie crust cookies.) Place each circle into one cavity of the prepared Whoopie Pie Pan. Add 1/8 cup sauteed apples to each unbaked pie crust shell. Evenly distribute crumble among all unbaked pies (pile it high).
Bake in oven for 10 minutes at 425 degrees F, then turn down temperature to 350 degrees for F and bake for 7 minutes more. Remove pies from the Whoopie Pie pan (they will release easily) immediately and place on a wire cooling rack.
In a small saucepan add all three ingredients for the drizzle and heat until melted together. Drizzle mixture evenly over the warm pies (make sure to constantly stir the mixture to keep it mixed together and not separated. This step is necessary to wet the crumble and apples below. Since the apples are cooked first, they are not releasing juice during the cooking process.)
For the sliced apples that go on top of the pies, add all ingredients to a nonstick skillet and saute over medium heat until softened, about 10 minutes. Place a couple of slices on top of each pie.
Serve with ice cream or whipped cream.