Reduce oven temperature from squash to 375 degrees. Combine water and cornmeal in a medium saucepan, stirring well. Bring to a boil and cook 1 minute, stirring frequently. Remove from heat and stir in milk and next 7 ingredients. Set aside. Beat egg whites at high speed of mixer until foamy. Add sugar, beating until stiff peaks form. Gently stir one-fourth of egg whites into cornmeal mixture. Gently fold in remaining whites, then roasted squash if desired at this point in the recipe. Otherwise, spoon mixture into a 2-quart casserole dish coated with cooking spray and then top with roasted squash. Bake for 50 minutes or until set. Yield: 6 servings.