In a large bowl, toss the first six ingredients. Pour into a greased 8-in. square baking dish.
In a bowl, combine oats, flour, brown sugar, baking powder and baking soda. Cut in butter until mixture resembles coarse crumbs. Sprinkle over apple mixture.
Bake at 350 degrees F for 55-60 minutes or until apples are tender and topping is golden. Serve warm with ice cream if desired.