1red bell peppercored and cut into 1-1/2-inch square pieces
1green bell peppercored and cut into 1-1/2-inch square pieces
1largetomatocored and cut into eighths
2celery ribssliced diagonally 1/2-inch thick
Freshly ground black pepper
2mediumonionssliced 1/2-inch thick
1/3cupgrated Parmesan cheese
Preheat oven to 425°F. Place zucchini, peppers, tomato, celery and garlic in a large bowl. Sprinkle with thyme, black pepper and two tablespoons of oil and toss to coat. Spread vegetables out on a large baking sheet in one layer. Set aside.
Pour remaining oil into a pie plate or 9-to-10-inch shallow pan and spread around evenly. Carefully place the sliced onions in the dish keeping them intact. Rub the bottom of the onions in the oil to coat them, then turn each slice over. Place vegetables and onions in oven and cook 25 to 30 minutes. Remove after 15 minutes and turn vegetables and onions over with tongs. They’re done when tender and brown. Season vegetables with salt. Let cool while making polenta. The vegetables are more flavorful served warm, not piping hot.
To make polenta: Bring water and salt to a boil in a medium-size saucepan. Reduce heat to medium and slowly whisk in cornmeal. Continue to whisk until polenta is thick and begins to pull away from sides of pan, about 7 minutes. Stir in butter and cheese. Serve polenta topped with roasted vegetables.