1.In A Large Saucepan, Combine Cornmeal And Salt. Gradually Add Boiling Water, Whisking Constantly. Cook And Stir Over Medium Heat For 5 Minutes Or Until Mixture Comes To A Boil. Remove From The Heat. Stir In Parmesan Cheese. 2.Spread Polenta Into A Greased 13-In. X 9-In. X 2-In. Baking Dish. Bake, Uncovered, At 350 Degrees F For 20 Minutes. Meanwhile, In A Large Skillet, Cook Sausage In Oil Over Medium Heat For 5 Minutes Or Until No Longer Pink; Drain. Add Spaghetti Sauce; Cook For 5 Minutes Or Until Heated Through. 3.Spread Over Polenta; Sprinkle With Mozzarella Cheese. Bake 12-15 Minutes Longer Or Until Cheese Is Melted. Let Stand For 15 Minutes Before Cutting.