1Heat oven to 450°F. In large roasting pan (do not use glass), place bell pepper, onion, zucchini, mushrooms and garlic. Drizzle with oil; sprinkle with salt and pepper flakes. Toss to coat evenly.
2Bake 15 minutes, stirring once halfway through baking. Add tomatoes; stir. Bake 15 to 20 minutes longer or until vegetables are tender and most of liquid has evaporated. Let stand 5 minutes.
3Stir vegetables. Serve over polenta or cooked pasta as desired.