In a large nonreactive saucepan, over medium heat, add the oil. Add the turkey sausage. Season with salt and pepper and mix well. Brown for 4 to 6 minutes. Add the onions, celery, and carrots. Season with salt and pepper. Cook for 4 to 5 minutes or until the vegetables are soft. Add the garlic and tomatoes. Season with salt and pepper. Continue to cook for 2 to 3 minutes. Whisk the tomato paste with the stock and add to the tomatoes. Add the thyme, bay leaves, oregano, basil and red pepper. Mix well.
Bring the liquid to a boil, reduce the heat to medium and simmer for about 2 hours. Stir occasionally and add more liquid if needed. During the last 30 minutes or cooking, reseason with salt and pepper and stir in the cheese. Remove from the heat and let sit for 15 minutes before using.
Yield: about 1 1/2 to 2 quarts