Preheat oven to 350 degrees. Spray 9 x 13-inch baking dish with baking spray.
In large bowl, mix together brown sugar, melted butter, flour, salt, cinnamon and mace.
Add squash and apples to the bowl, tossing to coat completely. Turn into baking dish and cover with foil. Bake for 1 hour or until squash and apples are tender.