Cream butter with both sugars. Stir in remaining ingredients until crumbly.
Toss filling ingredients together in a bowl and place in the bottom of a buttered 13x9x2-inch glass baking dish. Sprinkle evenly with the topping mixture.
Cover with aluminum foil and bake in a 400° F oven for 40 minutes. Remove foil and continue to cook until apples are soft and topping is well browned. Serve warm with a scoop of vanilla ice cream, sweetened whipped cream or creme fraiche.Makes 12