Preheat oven to 350 degrees. In a large bowl combine dry cake mix, one egg and 1 stick melted unsalted butter, mix completely. Pat cake mixture into the bottom of a 9x13 baking pan.
In the same bowl that you mixed the cake mix crust in combine cream cheese (be sure that this is super soft) and 1 stick melted unsalted butter. Once the cream cheese and butter and blended add the eggs one at a time. Be sure to mix well between each egg addition.
Add powdered sugar, pumpkin, vanilla, cinnamon and nutmeg to the filling mixture, stir well.
Pour filling over the cake mix crust. Place in the oven and bake for 50-55 minutes.
The center of the cake will still be slightly soft. Do not over bake.
Allow cake to cool before cutting. I love to serve this cake with whipped topping or caramel sauce and pecans!