Preheat your oven to 350°F and grease a 9-inch springform pan. In a large bowl, beat cream cheese until smooth, then gradually mix in sugar and flour. Incorporate vanilla and ground cinnamon, adding heavy whipping cream until combined. Beat in eggs, one at a time, ensuring a smooth batter. Bake for 10 minutes, then lower the temperature to 200°F and bake for an additional 30-35 minutes until the center jiggles slightly. Let it cool and refrigerate overnight.

While the cheesecake chills, preheat your oven to 350°F and prepare a cake pan. In a mixing bowl, whisk together all-purpose flour, baking powder, and your chosen spices. In a separate bowl, cream together butter and brown sugar until light. Mix in vegetable oil, eggs, and vanilla until fully combined. Gradually add the flour mixture and alternatingly mix in milk until smooth. Pour the batter into the pan and bake for 15-17 minutes until a toothpick inserted comes out clean. Cool completely and refrigerate overnight.

In a mixing bowl, beat unsalted butter on medium speed until fluffy, about 2-3 minutes. Gradually add powdered sugar, mixing well to incorporate. Stir in vanilla extract and a splash of heavy whipping cream, beating until you achieve a smooth, whipped consistency. If needed, adjust the thickness with more cream until you reach your desired frosting texture. Set aside while you assemble the Thanksgiving Piecaken.

Level each cake layer with a serrated knife to ensure even stacking. Begin by placing the chilled cheesecake layer on a serving stand. Spread a layer of frosting on top before carefully adding the spice cake layer. Frost the spice cake layer, then place the chilled pumpkin pie on top, trimming the crust as necessary. Frost the entire creation with remaining buttercream, smoothing out the edges for a clean finish.

Chill the assembled Thanksgiving Piecaken for at least an hour to set the layers firmly. For an elegant presentation, apply a final layer of frosting around the cake and sprinkle with optional ground cinnamon for added flavor. This stunning dessert is now ready to dazzle your guests at Thanksgiving.