Preheat over to 375 °.
Butter 13" by 9" baking dish.
Wash and peel apples.
Slice apples in about 1/4" slices.
Layer the apples on the buttered baking sheet.
Sprinkle the apples with water.
Combine the flour, sugar, cinnamon, and salt in a small bowl.
Add butter and blend with a pastry cutter. Dough will be crumbly.
Sprinkle dough on apples.
Bake for 50 minutes until the dough is golden brown and juices are bubbling.