Preheat your oven to 350 degrees F. Spray a 9-inch springform pan with non-stick spray and line the bottom with parchment paper.
In a stand mixer, cream 3 packages of softened cream cheese for approximately 5-6 minutes until smooth and fluffy. Gradually add ½ cup granulated sugar and 3 tablespoons all-purpose flour.
Stir in 1 teaspoon vanilla extract and 2 teaspoons ground cinnamon.
Add ½ cup heavy whipping cream to the mixture at low speed, then increase to high for about 1 minute. Add 2 large eggs one at a time, mixing thoroughly in between.
Pour the cheesecake batter into the prepared springform pan and gently tap it on the counter to release air bubbles. Bake at 350 degrees F for 10 minutes, then lower to 200 degrees F and bake for another 30-35 minutes.
Cool in the oven for 15 minutes before refrigerating overnight.
The following day, preheat the oven to 350 degrees F again, and prepare a 9-inch cake pan by greasing it with shortening and dusting with flour.
In a mixing bowl, whisk together ⅔ cup all-purpose flour, ½ teaspoon baking powder, and the spices.
In a stand mixer, cream together ¼ cup softened butter and ⅓ cup packed brown sugar until fluffy. Add 1 tablespoon vegetable oil, 1 large egg, and ½ teaspoon vanilla extract.
Gradually mix in half of the flour mixture, then pour in ⅓ cup plus 1 tablespoon of milk, followed by the remaining flour mixture. Mix until there are no dry spots left.
Pour the batter into the greased cake pan and bake for 15-17 minutes, checking for doneness.
Allow the cake to cool to room temperature before refrigerating overnight.
In a stand mixer, cream 12 ounces of softened unsalted butter until smooth. Gradually add 5 cups of powdered sugar.
Incorporate 2 teaspoons of vanilla extract and optionally, ½ teaspoon of cinnamon. Mix in 3-4 tablespoons of cold heavy whipping cream.
Trim the cheesecake and spice cake layers to the same size. Place the cheesecake layer upside down on a cake stand and spread ¾ cup frosting on top.
Gently place the spice cake layer on top and spread another ¾ cup frosting.
Remove the pumpkin pie from its dish, trim the crust, and place it on top. Cover with half of the remaining frosting and chill for 20-30 minutes.
Smooth the remaining frosting over the cake and pipe a decorative border if desired. Your Thanksgiving Piecaken is ready to serve!