Giada De Laurentiis offers a good recipe for marinara sauce featured on her show "Everyday Italian" on the Food Network. The recipe is available on FoodNetwork.com and calls for ingredients including extra virgin olive oil, onions, garlic, celery, carrots and tomatoes.
To start, heat 1/2 cup of extra virgin olive oil in a large sauce pot over medium to high heat. Add two small finely chopped onions and two finely chopped garlic cloves to the oil and sauté for about 10 minutes until the onions are softened and translucent. Add to the pot two peeled and finely chopped carrots, two stalks of finely chopped celery, 1/2 teaspoon of salt and 1/2 teaspoon of pepper to taste. Cook until all the vegetables are tender for roughly another 10 minutes.
Once the vegetables are cooked, add two 32-ounce cans of crushed tomatoes and their juices to the pot along with two dried bay leaves. Simmer the contents on low without a lid for about 1 hour until the sauce begins to thicken. Remove the bay leaves and season the sauce with more salt and pepper if necessary. Serve immediately with al dente pasta or cool, cover and refrigerate to save for later use.