• If you plan to make all-butter pie crust from scratch, you can use this my favorite all-butter pie crust recipe.
• Follow the instructions in the recipe to partially bake the pie crust and let it cool down completely before using. You can do this the day before. Once the pie crust have cooled down completely, cover with a cling wrap and it can be kept at room temperature until the next day
• If you plan to use store-bought, get the one for deep-dish 9-inch pie crust. Follow the instruction for full-baked pie crust and let it cool down completely before using

Prepare the apple filling: (can be prepared 2-3 days in advance)

• Peel, core and cut the apple into bite-size. I didn't peel the apple. Add the apple butter brown sugar, cinnamon, salt into a large pan/pot.
  
• Start with a medium heat and cook until the apples started to ooze out some juices and lower the heat a bit and continue to cook until the apples are soft
  
• Combine cornstarch with water to make a slurry. As you stir the apple mixture, add the cornstarch slurry and continue to stir until the mixture is thickened.
  
• Set aside to let it cool down, cover, and store in the fridge if not using on the same day
  

Prepare the pumpkin layer:

• Combine eggs, brown sugar, sugar, vanilla, pumpkin puree, all the spices, salt, and cream. Whisk until the mixture is creamy and smooth. Strain if needed
  

When ready to bake:

• 15 minutes before you plan to bake, preheat the oven to 400 F (230 C) for conventional oven, 430 F (220 C) for convection oven. Position the rack at the lowest level. Spread the apple pie filling at the bottom of the crust. Use a rubber spatula to smooth it out.
  
• Gently pour the pumpkin pie filling on top of the apple pie. Pop any visible air bubbles and smooth with a rubber spatula
  
• Place the assembled pie on top of a baking pan (to catch any dripping juices). Bake for 30-35 minutes and check. The edges are puffed and the center just set. A very slight jiggle at the center is fine. The pie continues to firm up as it cools down. If it's too jiggly, bake for another 5 minutes and check again
  

Cool down and chill before serving:

• Let the pie cool down completely for 4-6 hours. This pie is best served cold. So after it has cooled down completely. I highly recommend to cover it and keep it in the fridge overnight.
  

To serve:

• Serve the pie as is or with some whipped cream