Petra's Tomato Sauce

Makes 12 cups sauce, about 12 servings

About 3 tablespoons olive oil
1 medium onion, finely chopped
3 garlic cloves, finely chopped
1 1⁄2 pounds mushrooms
6, 15 ounce cans of organic tomato sauce
1, 6 ounce can tomato paste
3 tablespoons dried herbs (any combination of thyme, rosemary, oregano, or sage)

In a large pot heat the olive oil over medium low heat. Add the onions and cook, stirring occasionally, until translucent and softened, about 10 minutes. While the onions are cooking finely chop the mushrooms in a food processor. Add the mushrooms and the garlic to the pot. Increase to medium high heat and cook the mushrooms, stirring frequently, until any liquid has evaporated and the mushrooms are cooked, about 10 minutes. Add the tomato sauce and the tomato paste. Fill each of the jars of tomato sauce up with water and add to the pot. Stir in the herbs. Bring to a boil and then reduce to a medium low boil. Cook for about 1 1⁄2 hours, stirring frequently (especially when the sauce begins to thicken) until the sauce is reduced and thickened.