Preheat your oven to 350°F (175°C). In a mixing bowl, beat the cream cheese until it’s smooth and creamy. Add granulated sugar, flour, vanilla extract, and ground cinnamon, mixing until well combined. Gently fold in the heavy whipping cream and eggs until just incorporated. Pour this luscious mixture into a prepared springform pan and bake for 10 minutes, then reduce the temperature to 200°F (95°C) and bake for an additional 30-35 minutes. The cheesecake should be set in the center but slightly wobbly.

While the cheesecake cools, preheat your oven again to 350°F (175°C). In a bowl, cream together the butter and brown sugar until fluffy, then mix in the vegetable oil and egg. In a separate bowl, whisk together the all-purpose flour, baking powder, and your desired spices. Gradually add the dry ingredients to the wet mixture, alternating with milk, until a smooth batter forms. Pour into a greased cake pan and bake for 15-17 minutes, or until a toothpick inserted comes out clean. Allow the cake to cool completely.

Once your cheesecake and spice cake layers are cooled, let's whip up the buttercream! In a large bowl, beat the unsalted butter on medium speed until fluffy, about 2-3 minutes. Gradually add the powdered sugar, mixing well after each addition. Add vanilla extract and heavy whipping cream, beating until the frosting reaches your desired consistency—fluffy and spreadable.

Now it’s time to layer your Thanksgiving Piecaken! Carefully trim the cheesecake and spice cake layers to ensure they are even. Start with the cheesecake layer as your base, spreading a layer of buttercream on top. Next, add the spice cake, pressing down gently before frosting the top again. Place the store-bought pumpkin pie on top of the spice cake, then add a final layer of buttercream to create a beautiful finish. Refrigerate for 20-30 minutes to firm everything up before serving.