Tomato Ketchup

omato sauce refers to any of a very large number of sauces made primarily from tomatoes, usually to be served as part of a dish (rather than as a condiment). Tomato sauces are common for vegetables, but they are perhaps best known as sauces for pasta dishes. Tomatoes have a rich flavor, high liquid content, very soft flesh which breaks down easily, and the right composition to thicken into a sauce when they are cooked. All of these qualities make them ideal for simple and appealing sauces.
Water is sometimes added to keep it from drying out too much. Onion and garlic are almost always sweated or sautéed at the beginning before the tomato is added. Other seasonings typically include basil, oregano, parsley, and possibly some spicy red pepper or black pepper.