I got this recipe from Michael Chiarello's Nappa Valley website and the sauce was absolutely fantastic.
1-1/2 cups marinara sauce (recipe follows)
1/4 cup clam juice (preferably unsalted)
2 teaspoons anchovy, chopped and smashed
2 teaspoons salted or canned capers, rinsed and chopped
1 tablespoon finely chopped fresh oregano
2 tablepoons finely chopped Italian flat leaf parsley
1-1/2 teaspoons red wine vinegar
1-1/2 teaspoons finely chopped hot chili peppers (oil packed from Italy)
2 tablespoons extra virgin olive oil
1/2 cup Kalamata and Picoline olives, pitted and quartered
1/2 cup fresh tomatoes, peeled, seeded, and diced into 1/2" pieces
12 ounces cooked penne or rigatoni
What I did to peel the tomatoes was on the end of each tomato cut an x. Put into some simmering water for a few minutes, take out, and the pell should come right off. I didn't worry about seeding it though.
Whisk the marinara sauce and clam juice together. Add the remaining ingredients, except the pasta, and add additional seasoning to taste.
Just before serving, warm the sauce and toss with the hot pasta.
This versatile sauce can be made up to a week ahead. Toss with pasta, or spoon over grilled shrimp, halibut, or swordfish.
2 tablespoons extra-virgin olive oil
1/2 cup minced onion
1 tablespoon chopped fresh Italian parsley leaves
1 large clove garlic, minced
4 cups fresh tomato puree
1 large fresh basil stem with leaves removed
1 teaspoon sea salt, preferably gray salt
Pinch baking soda or sugar, if needed
Heat the olive oil in a large non-reactive pot over moderate heat. Add the onion and saute until translucent, about 8 minutes. Add the parsley and garlic and cook briefly to release their fragrance. Add the tomatoes, basil and salt. Simmer briskly until reduced to a sauce like consistency, stirring occasionally so nothing sticks to the bottom of the pot. The timing will depend on the ripeness and meatiness of your tomatoes and the size of your pot. If the sauce thickens too much before the flavors have developed, add a little water and continue cooking.
Taste and adjust the seasoning. If the sauce tastes too acidic, add the baking soda and cook for 5 more minutes. If it needs a touch of sweetness, add the sugar and cook for 5 more minutes. Remove the basil stem before serving.