1Preheat oven to 375. Spray 13x9 baking pan with non-stick spray. Peel, core and slice apples.
2In medium bowl, combine sugar, cornstarch, cinnamon, and salt. Sprinkle over cut apples in baking pan. Dot with butter.
3In a food processor or mini chopper. combine brown sugar, flour, oats, cinnamon and salt. Pulse processor until mixture is small but not fine.
4Mix with melted butter until it reaches a crumbly consistency. Sprinkle mixture evenly on top of apples.
Bake until apples are tender and topping is golden brown; about 1 hour. Let rest for 10-15 minutes before serving.