Preheat oven to 300 and spray a 9×13 dish with cooking spray. Mix cake mix, melted butter and one egg to a soft dough. Press into the bottom of the pan. Mix powdered sugar, softened cream cheese and remaining two eggs and vanilla and beat until smooth, about 1-2 minutes. Pour on top of crust. Bake at 300 for 40-50 minutes until top is golden brown.