Combine the first 6 ingredients in a bowl; stir well. Cut in margarine with a pastry blender until mixture resembles coarse crumbs; set aside.
Coat an 8-inch square baking dish with cooking spray. Place apple slices in the dish; drop apricot preserves by teaspoonfuls onto apple slices. Sprinkle evenly with the flour/nut mixture. Bake at 375° for 35 minutes or until bubbly and golden.
Serve warm, topped with vanilla ice cream or whipped cream if desired.