Preheat your oven to 350°F (175°C) and grease a 9-inch springform pan. In a large mixing bowl, blend softened cream cheese, granulated sugar, and flour until smooth and creamy. Gradually add vanilla extract, ground cinnamon, and heavy whipping cream, mixing until combined. Incorporate eggs one at a time, ensuring each is well blended. Bake for 10 minutes at 350°F, then reduce the temperature to 200°F (93°C) for 30-35 minutes until the center jiggles slightly. Chill overnight in the refrigerator.

While the cheesecake chills, preheat the oven to 350°F (175°C) again. In a mixing bowl, combine all-purpose flour, baking powder, and ground spices, stirring well. In a separate bowl, cream together unsalted butter and brown sugar until fluffy. Gradually add the dry ingredients, alternating with milk to create a smooth batter. Pour into a greased cake pan and bake for 15-17 minutes or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely before wrapping it and refrigerating overnight.

The next day, whip up the buttercream frosting. In a mixing bowl, beat softened unsalted butter until fluffy and pale. Gradually add powdered sugar, mixing well to avoid lumps. Stir in vanilla extract and enough heavy whipping cream to achieve a smooth, spreadable consistency. If desired, sprinkle in optional cinnamon for extra flavor. Set aside while you assemble the Thanksgiving Piecaken.

Trim each layer to ensure they match in size for perfect stacking. Start with the cheesecake layer on your serving platter, followed by the spice cake layer, and top it off with the store-bought pumpkin pie. Evenly spread the buttercream frosting around and over the entire assembled dessert, smoothing it out with a spatula. Chill the assembled piecaken briefly to set the frosting before slicing and serving.