Preheat oven to 350°F (175°C) while you prepare your layers.

In a large mixing bowl, combine cream cheese until smooth, then gradually mix in granulated sugar and flour. Blend in vanilla, ground cinnamon, heavy cream, and eggs until well incorporated.

Pour the cheesecake mixture into a prepared springform pan, bake for 10 minutes, then reduce temperature to 200°F (93°C) and bake for another 30-35 minutes until just set. Allow to cool, then refrigerate overnight.

Preheat your oven again to 350°F (175°C) if turned off, then grease and flour your cake pan. In a separate bowl, whisk dry ingredients. Cream softened butter and brown sugar until fluffy, then add vegetable oil, egg, and vanilla. Mix in flour and milk until smooth.

Pour batter into prepared cake pan and bake for 15-17 minutes or until a toothpick comes out clean. Cool completely, then refrigerate overnight.

In a mixer, whip softened unsalted butter until light and fluffy. Gradually add powdered sugar, mixing until combined. Add optional cinnamon, vanilla extract, and cold heavy whipping cream until achieving a light and airy texture.

Trim the cooled layers for evenness. Stack the cheesecake on your serving platter, followed by the spice cake, topping with the pumpkin pie. Frost with buttercream, refrigerate for at least 30 minutes, then frost completely and prepare for serving.