I baked two of these for a church bake sale. My son loves these so much that he was going to buy one of them back from the church. They both sold though, so I owe him one. It really isn't a cake-it's more like bar cookies with a cream cheese topping. The cream cheese is mixed with butter and powdered sugar so that when it bakes, a toasted marshmallow-like top is created. That is why it has cracks on top. It is crispy and toasted on top, gooey underneath.
Paula Deen's Gooey Butter Cake: preheat oven to 350 degrees. In a mixing bowl, cream one box of yellow cake mix, one stick of melted butter and one egg. It will be very thick. Pat out the crust into a 9x13 pan.
In the same mixing bowl, cream 8 oz. cream cheese, 2 eggs, one stick of melted butter, 1 teaspoon vanilla and 1 lb. of powdered sugar. Pour over the crust and bake for about 40 minutes. It should be golden brown on top but still jiggly in the middle. Cool completely. Very rich and sweet!