Preheat oven to 375F..Spray 11 x 7 inch baking dish with cooking spray. In medium combine bowl combine cornmeal and 1 cup water..set aside. In large saucepan bring 1 1/3 cups water to a boil, reduce heat to low and stirring constantly gradually add the cornmeal mixture,,stirring often cook for 10 minutes, until mixture is thickened. Remove from heat and stir in half the cheese..transfer cornmeal mixture to prepared baking dish, smooth top and set aside.
In large non-stick skillet heat oil add onions and garlic..cook over medium heat stirring frequently for 7 minutes and onions are golden brown, add mushrooms and bell pepper and cook until pepper is softened...add tomatoes and basil and pepper flakes reduce heat to low, cover and cook on low heat for another 5 minutes.
Spoon tomato mixture over cornmeal and sprinkle with remaining cheese..bake 20 minutes until heated through and sauce is bubbly.