Preheat the oven to 350 degrees. Spray two 8-inch round cake pans with cooking spray. Line the bottoms of the pans with parchment paper, then generously spray the pans with cooking spray again. Set aside.

Beat the cream cheese, sugar, and flour together with an electric mixer set to medium speed. Beat in eggs and egg yolks one at a time, mixing until eggs are just incorporated. Scrape down the sides and bottom of the bowl. Turn mixer to low and beat in the sour cream, heavy cream, vanilla, cinnamon, and ginger.

Divide batter evenly between the prepared pans and smooth the tops. Set pans in a roasting pan (or any large baking pan) and carry over to the oven. Pour a couple inches of water into the roasting pan, then carefully transfer to the oven. Bake 38 to 44 minutes, until the center of the cheesecakes barely wobbles. Remove from the oven and immediately run a knife between the cake and the edge of the pan. Cool cheesecakes to room temperature. Once cooled, cover with plastic wrap and refrigerate overnight.

After the cheesecake layers have refrigerated, dip the pan in a bowl of hot water for about 15 seconds. Run a knife around the edge of the cake again, then set a large plate or a cake circle on top of the pan. Invert the cakes onto the plate. Keep refrigerated until you assemble the cake.

Preheat the oven to 350 degrees. Spray 3 8-inch round cake pans with cooking spray. Lightly dust with flour; tap out the excess flour and set pans aside.

Whisk the flour, baking powder, baking soda, salt, and spices together in a medium mixing bowl.

In another large mixing bowl, combine the oil, eggs, sugars, pumpkin, buttermilk, and vanilla. Beat with an electric mixer set to medium speed until smooth. Fold the flour mixture into the pumpkin mixture until just combined. Divide batter evenly between the prepared pans and bake until a cake tester inserted into the center of the cakes comes out clean, 30 to 40 minutes. Cool for 10 minutes in the pans, then carefully invert onto wire racks to cool completely before assembling your cake.

Place the butter in a medium mixing bowl and beat with an electric mixer until very smooth. Beat in 4 cups of the sugar, mixing until well incorporated. Beat in an additional 4 cups sugar along with the vanilla and the salt. Mix until smooth, then beat in the caramel sauce until well combined. Add milk to thin the frosting or powdered sugar to thicken it.

Place one of the cooled pumpkin layers on a cardboard cake circle or a cake stand. Spread a thin layer of frosting over the top. Top with one of the cheesecake layers. Spread a thin layer of frosting over the cheesecake, then top with another pumpkin layer; repeat with remaining cheesecake and cake layers.

If your cheesecake layers are a little wider than your pumpkin layers, run a sharp paring knife around the edge of the cake to trim the excess cheesecake. Frost your cake with a thin layer of the remaining caramel frosting and refrigerate until frosting sets (this is your crumb coat and will prevent crumbs from getting into the final layer of frosting). Frost with remaining frosting and decorate as desired. Serve and enjoy.