Preheat oven to 350 degrees. Mix apples, white sugar, and cinnamon thoroughly in a bowl. Pour into an ungreased 7×11-inch baking dish. Mix brown sugar, flour, and butter in a bowl to make a crumble. Sprinkle crumble over top of the apple mixture. Bake until the apples are bubbling and the crumble is lightly browned, about 45 to 60 minutes. Serve warm. Delicious all by itself, or with a scoop of vanilla ice cream on top.