For filling: Preheat oven to 375 degrees F. In a large bowl combine apples, 2 tablespoons sugar or sugar substitute, lemon juice, and 1/2 teaspoon of the apple pie spice. Transfer apple mixture to a 2-quart square baking dish.

For topping: In medium bowl, combine oats, 1/4 cup sugar or sugar substitute, flour, and 1/4 teaspoon apple pie spice. Cut in butter until mixture resembles coarse crumbs. Sprinkle topping over filling.

Bake for 30 to 35 minutes or until apple is tender and topping is golden brown. Serve warm. If desired, top with whipped topping.