Preparation
Preheat your oven to 350°F (175°C). Thoroughly grease two 9-inch round cake pans and line them with parchment paper at the bottom. This ensures easy removal after baking and prevents the cake from sticking to the pan.
Bake Spice Cake Layers
In two separate mixing bowls (or one at a time), prepare each spice cake mix according to the ingredients list. Combine one box of spice cake mix with 3 eggs, 1/2 cup vegetable oil, and 1 cup water, mixing until smooth and well incorporated. Pour the batter into the prepared pans and bake according to package directions, typically 28-32 minutes, until a toothpick inserted in the center comes out clean. Allow the cakes to cool completely before removing from pans.
Create the Gooey Pumpkin Filling
In a large bowl, beat the softened cream cheese and pumpkin puree until completely smooth and no lumps remain. Add the eggs, vanilla extract, and melted butter, continuing to beat until the mixture becomes creamy and well combined. Gradually mix in the powdered sugar, pumpkin pie spice, and cinnamon until fully incorporated. Pour this mixture into a greased 9-inch pan and bake for 45-50 minutes. The edges should be set while the center remains slightly gooey. Let it cool completely before carefully removing from the pan.
Make the Brown Sugar Cream Cheese Frosting
In a mixing bowl, beat the softened cream cheese, butter, and brown sugar until light and fluffy, about 3-4 minutes. Gradually add the powdered sugar, vanilla extract, and heavy cream, beating until the frosting is smooth and reaches a spreadable consistency. If needed, adjust the thickness by adding more cream or powdered sugar.
Assemble the Cake
Place one spice cake layer on a serving plate as your base. Spread a thin layer of frosting over this layer to help the next layer adhere. Carefully position the gooey pumpkin layer on top of the frosted cake layer. Place the second spice cake layer on top of the pumpkin layer. Cover the entire cake with the remaining brown sugar cream cheese frosting, spreading it evenly on the top and sides.
Chill and Serve
Refrigerate the cake for 30-60 minutes before slicing to help it set properly. For an extra special presentation, consider garnishing with a drizzle of caramel sauce, a sprinkle of crushed gingersnaps or spiced pecans, and a light dusting of cinnamon sugar before serving.
