In a large bowl, whisk together all ingredients for pie filling until well combined.
Place the frozen pie crust on a baking sheet and then fill the crust with the pumpkin pie filling. Combine the melted butter, cinnamon, and sugar.
Very gently toss the apple slices in the butter mixture to coat.
Begin with the larger slices and shingle in a circle just inside the crust.
Repeat with smaller slices until they come together in the middle.
Bake for 15 minutes, then lower the oven to 350 and cook for 15-20 minutes more until set. Allow to cool completely.
Slice and serve!