Preheat oven to 350 degrees. Spray a 9×13 pan with cooking spray.
Peel and slice apples; coat with the brown sugar and cinnamon by mixing together with a spoon or your hands, and placing in a 9×13 pan.
Mix the next 5 ingredients together (butter, sugar, flour, salt, eggs) to make a crumble. Place on top of the apple mixture.
Bake at 350 for 1 hour.
Make the custard:
To make the custard, in a saucepan over medium heat, stir together the sugar, cornstarch, salt, eggs, and cream. Stir constantly until smooth and thick. Stir in 1 tsp. vanilla.