Combine apple pieces, sugar, cinnamon, flour, lemon juice, and water in mixing bowl; set aside.
In the bowl of a stand mixer, combine flour, brown sugar, quick oats, butter to form the crumble.
Pour apple mixture into an ungreased 8x8 baking dish. Cover evenly with crumble.
Bake 350° for 45 minutes, or until crumble turns light golden brown and apple mixture starts to bubble. Serve hot with vanilla ice cream. Enjoy!