3 tablespoons of olive oil 2 large garlic cloves minced 1 large carrot, finely chopped 2 celery stalks, finely chopped 1 small onion, finely chopped 1/3 cup finely chopped pancetta or bacon (optional) 6 peeled, seeded and chopped ripe roma tomatoes (or about 1 (14 ounce) can chopped tomatoes) 1 quart chi