Polenta with Quick Fire Roasted Tomato and Bell Pepper Sauce

Ingredients

• 1 tablespoon olive oil
• 2 medium yellow onions, halved and cut into 1/4-inch slices
• 1 red bell pepper, seeded, cored and cut into 1/4-inch slices
• 1 yellow bell pepper, cored and cut into 1/4-inch slices
• 1 orange bell pepper, cored and cut into 1/4-inch slices
• 2 cloves garlic, finely chopped
• 1 can (14.5 oz) Muir Glen™ Organic Fire Roasted Crushed Tomatoes, undrained
• 1 tablespoon red wine vinegar
• 1/4 teaspoon red pepper flakes
• 1/2 teaspoon fine sea salt or kosher salt
• 1/4 teaspoon black pepper
• 6 cups water
• 3/4 teaspoon fine sea salt or kosher salt
• 1 1/2 cups coarse-ground cornmeal
• 1 tablespoon butter
• 1/4 cup shredded Parmesan cheese, plus additional for garnish
• Chopped green onion, if deired