Preheat oven to 350°F. Grease a 9x13-inch baking pan with nonstick spray. Set aside.
Combine the cake mix, egg, and butter and mix well with a hand mixer. Pat the mixture into the bottom of the prepared baking pan. Set aside while you make the filling.
18 ounces yellow cake mix, 1 large egg, 8 tablespoons unsalted butter
In a large bowl, using a hand mixer, beat the cream cheese and pumpkin until smooth.
8 ounces cream cheese, 15 ounces pumpkin puree
Add the eggs, vanilla, and butter, and beat together.
3 large eggs, 1 teaspoon pure vanilla extract, 8 tablespoons unsalted butter
Add the powdered sugar, cinnamon, nutmeg, and mix well.
16 ounces powdered sugar, 1 teaspoon ground cinnamon, 1 teaspoon ground nutmeg
Spread the pumpkin mixture over the cake batter and bake for 40 to 50 minutes. Be conscious not to overbake; the center should be slightly gooey. You won't regret it :)
You can serve it plain, or top with whipped cream, pecans, caramel, or more powdered sugar.
Caramel sauce, Chopped pecans, Whipped cream