My starting point was the Pumpkin Ganache from the Milk Bar Cookbook. It's basically a mixture of pumpkin purée and white chocolate, smoothed out with some glucose. I was able to buy glucose at Joann in the cake decorating section. It's pumpkin-y, but isn't spiced like pumpkin pie. I made a double recipe.
To add spice, I made a Cinnamon Brown Sugar Cake, based on the Triple Browned Cake from Completely Delicious. To that recipe I added 1 tablespoon cinnamon, 1½ teaspoon ground ginger, ½ teaspoon ground cloves, and ½ teaspoon grated nutmeg. I baked the cake in three 9-inch cake pans.
The original cake has a liquid cheesecake layer; I love pumpkin cheesecake, so I knew the flavors would work together. I doubled the recipe and baked the cheesecake in an 8-inch round cake pan, which has approximately the same volume as two of the 6-inch square pans called for.
The pie crumbs are very easy and delicious. I made a double recipe, but had a bunch left over. I'll save them for another dessert.
I made all the components on Monday and Tuesday, assembled the cake Wednesday, and served it Thursday.
I assembled the cake in my 8" Cake Pan with Removable Bottom. A springform pan would work equally well in place of the cake ring. The Bakery at Wegmans gave me three acetate strips after I called and asked about them. I wouldn't have wanted to make the cake without them, and I didn't have enough time for an online order.
I trimmed the cakes to 8-inches by cutting around the base of an 8-inch cake pan. I also trimmed and leveled the tops of the cakes.
I lined the cake pan and put in the bottom layer, then spread the liquid cheesecake over.
I sprinkled on the pie crumbs.
I piped the pumpkin ganache using the cake icer tip because the ganache was the most firm element. I tried to push each element up to the edges evenly, and wiped the inside of acetate after each layer. I then did the same again, adding the next piece of acetate.
I froze the cake overnight, and removed it from the pan the next day.
Instead of frosting, I mixed 1 cup heavy cream, ½ cup sour cream, and ½ cup brown sugar, then let it sit 4 hours in the refrigerator. I whipped it right before serving, the spread it level with the top of the acetate.
The key to making these cakes attractive is to layer very evenly and spread each layer to the edge. I forgot that I was supposed to take the acetate off when the cake was still frozen, so the sides weren't as smooth as they would have been otherwise.
The flavor was the best part. The combination was much better than any individual component. I was very proud, and can't wait to make more cakes like this in the future.