Preheat oven to 350 degrees. Grease a 9x13 inch pan and set aside.
In a Large mixing bowl add the cake mix, egg, and melted butter and stir together until incorporated. Press into the bottom of your 9x13 inch pan. Set aside.
To make the filling: In a Large mixing bowl beat the cream cheese until smooth. Add the eggs one at a time and continue to beat until smooth. Add the vanilla, lemon juice, powdered sugar, and melted butter. Pour over the cake mix.
For the topping: In a medium sized bowl combine the brown sugar and white sugar. Mix in the coconut and stir in the butte and flour. Sprinkle on top of the filling.
Bake in preheated oven for 35-40 minutes. You want the center to be gooey but set and the top is lightly brown. Allow to cool before cutting into squares.