Beat butter at medium speed of an electric mixer until creamy. Gradually add sugar; beat well. Add milk and egg; beat well. Stir in flour mixture; set batter aside.
Combine sliced apple and next 4 ingredients in a large bowl. Combine cornstarch and water. Add to apple mixture; stir well. Spoon apple mixture into a lightly greased 11" x 7" x 1 1/2" baking dish. Drop batter by spoonfuls over fruit mixture. Bake, uncovered, at 350° for 45 or 50 minutes or until golden. If desired, serve warm with Vanilla Bean Hard Sauce or ice cream.