3 pounds (about 20 medium) fresh plum tomatoes, cored, peeled, seeded, and pureed (enough to yield 4 cups)
1/4 cup minced fresh parsley, or 1 tablespoon dried
3 tablespoons minced fresh basil, or 1 teaspoon dried
1 tablespoon minced fresh oregano, or 1 teaspoon dried
salt and pepper, to taste
Turn the slow-cooker on high, let it heat for 5 minutes, and add olive oil, onion, and garlic. Stir and cover. (The pot won't get hot enough to brown them.) Cook for 1 hour, or until onion is soft and wilted. Uncover and add tomatoes, parsley, basil, oregano, salt, and pepper. Reduce the heat to low, and stir. Cook with the cover off for approximately 4 hours. The sauce is done when it is thick and not watery.
Tip: If ladeled into hot, sterilized jars and refrigerated, tomato sauces like the one above will last for several weeks. For long-term preservation, process in a boiling-water bath.