In a large bowl, toss the first four 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° for 55-60 minutes or until apples are tender and topping is golden. Serve warm with ice cream if desired.