Preheat your oven to 350°F (175°C). Grease a 10-inch springform pan (at least 3 inches deep) thoroughly with butter or baking spray. Line the bottom with a round of parchment paper and grease the parchment.

Prepare the pies. Ensure they are fully chilled and firm. If the crusts have a tall, fluted edge, carefully trim them so the pie is relatively flat and can fit inside the pan with about a 1/2-inch gap around the edge.

In a large bowl, whisk together the sifted flour, baking powder, baking soda, cinnamon, ginger, nutmeg, allspice, cloves, and salt. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), beat the softened butter, brown sugar, and granulated sugar on medium-high speed until light and fluffy, about 3-4 minutes.

Add the room temperature eggs one at a time, beating well after each addition and scraping down the sides of the bowl as needed. Beat in the vanilla extract.

Reduce the mixer speed to low. Add the dry ingredients in three additions, alternating with the buttermilk in two additions, beginning and ending with the dry ingredients. (Dry, Buttermilk, Dry, Buttermilk, Dry). Mix only until just combined—do not overmix.

Spread about one-third of the spice cake batter (approx. 3 cups) evenly into the bottom of the prepared springform pan.

Carefully un-pan the chilled pecan pie and center it upside down on top of the batter layer. Gently press it down.

Pour another third of the batter over the pecan pie, using a spatula to spread it evenly over the top and down the sides to fill any gaps.

Next, place the chilled pumpkin pie upside down on top of the second batter layer. Gently press down.

Pour the remaining cake batter over the top, spreading it to completely cover the pumpkin pie and seal the cake. The batter should be about 1/2 inch from the top of the pan.

Place the pan on a baking sheet to catch any potential drips. Bake for 90-105 minutes. After about 60 minutes, if the top is browning too quickly, tent it loosely with aluminum foil. The cake is done when a long wooden skewer or cake tester inserted into the cake part (avoiding the pies) comes out with a few moist crumbs attached.

Let the Piecaken cool completely in the pan on a wire rack for at least 3-4 hours. Once at room temperature, cover and transfer to the refrigerator to chill for at least 6 hours, or preferably overnight. This step is crucial for stability.

In a large bowl using an electric mixer, beat the softened cream cheese and butter together on medium speed until smooth and creamy, about 2 minutes.

With the mixer on low, gradually add the sifted powdered sugar, cinnamon, and salt. Once incorporated, increase the speed to medium-high and beat for 2-3 minutes until light and fluffy. Beat in the vanilla extract.

Once the cake is thoroughly chilled, carefully run a thin knife around the edge of the springform pan and release the sides. Transfer the cake to a serving platter. Frost the top and sides with the cinnamon cream cheese frosting. Garnish with chopped pecans or a sprinkle of cinnamon, if desired.

For the cleanest slices, use a long, sharp knife, and wipe the blade clean between each cut. Keep the Piecaken refrigerated until ready to serve.