Preheat your oven to 350°F (175°C). In a mixing bowl, beat the softened cream cheese until smooth and creamy. Gradually mix in granulated sugar, flour, vanilla extract, ground cinnamon, and heavy whipping cream until well combined. Add the eggs one at a time, mixing gently after each addition. Pour this rich mixture into a greased springform pan and bake for 10 minutes, then reduce the temperature to 200°F (93°C) and continue baking for 30-35 minutes, or until the center is slightly jiggly. Cool the cheesecake completely, then refrigerate overnight.

While the cheesecake cools, preheat the oven again to 350°F (175°C). In a large mixing bowl, whisk together all-purpose flour, baking powder, and spices. In a separate bowl, cream the softened butter with brown sugar until fluffy, then add vegetable oil, eggs, and milk, mixing until smooth. Gradually incorporate the dry mixture into the wet ingredients until just combined. Pour the batter into a greased cake pan and bake for 15-17 minutes, or until a toothpick comes out clean. Allow to cool, then refrigerate overnight.

In a mixing bowl, beat softened unsalted butter until fluffy and pale. Gradually add powdered sugar and a sprinkle of ground cinnamon, mixing until fully integrated. Drizzle in the vanilla extract and heavy whipping cream while continuing to beat until the frosting is light and fluffy.

Once all layers are chilled and firm, carefully trim any domed tops of the cheesecake and spice cake for even stacking. Start by placing the cheesecake layer on a serving stand and spread a layer of frosting on top. Gently place the spice cake layer over the cheesecake and frost the top generously. Finally, add your store-bought pumpkin pie on top, frosting the outer sides.

After chilling, your Thanksgiving Piecaken is ready to be served! Carefully slice through the layers so everyone can enjoy the delightful contrasts of flavors.