For polenta, in a medium saucepan bring 2 1/2 cups of the water to boiling. In a medium bowl combine the remaining 1 1/2 cups water, the cornmeal, and the 1 teaspoon salt. Slowly add cornmeal mixture to boiling water, stirring constantly. Cook and stir until mixture returns to boiling; reduce heat to low. Cook about 10 minutes or until mixture is very thick, stirring occasionally. Pour the hot mixture into a 3-quart rectangular baking dish. Cool slightly. Cover and refrigerate about 1 hour or until firm. (Or, cover and refrigerate up to 24 hours.)

In a large nonstick skillet cook onion in hot oil over medium heat for 3 to 4 minutes or until tender. Add mushrooms, the 1/4 teaspoon salt, and the black pepper. Cook and stir about 5 minutes or until mushrooms are tender. Remove from heat; stir in the green and red roasted sweet peppers.

Spread the marinara sauce over chilled polenta. Top with the vegetable mixture and sprinkle with mozzarella cheese. Bake, covered, in a 350 degree oven for 30 minutes. Bake, uncovered, for 10 to 15 minutes more or until edges are bubbly. Makes: 8 servings