Preheat your oven to 350°F (175°C). In a mixing bowl, cream together softened cream cheese until smooth and fluffy, about 2 minutes. Gradually add granulated sugar, flour, vanilla extract, and ground cinnamon, mixing until just combined. Slowly blend in heavy cream and eggs until the mixture is smooth. Pour the batter into a prepared springform pan and bake for 10 minutes. Lower the temperature to 200°F (95°C) and continue baking until slightly jiggly in the center, about 30–35 minutes. Allow the cheesecake to cool and then refrigerate overnight.

While the cheesecake cools, preheat the oven to 350°F (175°C) again. In a large mixing bowl, cream butter and brown sugar until light and fluffy, about 3–4 minutes. Add oil, large egg, and vanilla extract, mixing well. In a separate bowl, whisk together all-purpose flour, baking powder, and your chosen spices. Gradually incorporate the dry ingredients into the wet mixture, alternating with milk. Pour the cake batter into a greased cake pan and bake for 15–17 minutes, or until a toothpick inserted comes out clean. Once baked, let it cool completely, then refrigerate overnight.

With your cake layers chilling, it's the perfect time to make the frosting. In a mixing bowl, beat softened unsalted butter on medium speed until fluffy, about 2 minutes. Gradually add powdered sugar and mix until well combined, then add vanilla extract and optional cinnamon for flavor. To achieve a light texture, mix in heavy whipping cream until the frosting becomes thick and airy. This step should take about 3–4 minutes, creating a delicious frosting for your Thanksgiving Piecaken.

Once your cheesecake and spice cake layers are completely cooled, it’s assembly time! Trim the edges of each layer for an even finish. On a cake stand, place the cheesecake as the base layer and generously frost the top. Next, carefully layer the spice cake over the cheesecake, adding another layer of frosting on top. Finally, place the store-bought pumpkin pie on top of the spice cake and cover the entire assembled dessert with the remaining frosting. Ensure the frosting is smooth and even for a beautiful finish.

After assembling your Thanksgiving Piecaken, refrigerate it for about 30 minutes to set the frosting. Once chilled, remove from the refrigerator, and slice into generous pieces. Serve with a sprinkle of cinnamon on top or a dollop of whipped cream, if desired.