Peel squash and cut in half lengthwise; scoop out seeds. Cut squash into thin slices. In a large bowl, combine the squash, apples, corn syrup and lemon juice; toss to coat. In a small bowl, combine the brown sugar, cornstarch, cinnamon and salt. Add to squash mixture; mix well.
Transfer to a 13-in. x 9-in. baking dish coated with cooking spray. Cover and bake at 375° for 20 minutes.
For topping, in a bowl, combine the flour, oats and brown sugar; cut in butter until mixture resembles coarse crumbs. Sprinkle over squash mixture. Bake, uncovered, for 25 minutes or until squash and apples are tender and topping is lightly browned. Serve with ice cream or whipped cream.