Heat oven to 425°. Grease a 13x9x2 inch baking pan. Mix cornmeal, milk and salt in a 2-quart saucepan. Cook over medium high heat, stirring constantly, until mixture thickens and boils; reduce heat. Cover and simmer 10 minutes, stirring occasionally; remove from heat. Stir in 1/2 cup parmesan cheese. Cool 30 minutes. Spread on bottom of baking dish and up sides about an inch. Cook onion, green pepper, mushrooms and garlic in oil in an 8-inch skillet over medium high heat, stirring occasionally, until crisp tender. Spread marinara over cornmeal mixture. Top with cooked vegetables. Sprinkle with cheese and basil. Bake 18-20 minutes or until thoroughly heated and cheese is melted and light golden brown. Let stand 10 minutes.
Mary Ann Dowd submitted these two recipes for Polenta Pizza, from Betty Crocker cookbook, and The Best Pizza Dough.