Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   2      tablespoons   olive oil
   2      medium        onions -- chop
   3      cans          imported Italian tomatoes -- crush, drain, 28oz
                        -- e
   1      bunch         fresh basil -- chop
   1      pinch         crushed red pepper flakes
   1      tablespoon    unsalted butter
   2      pounds        spaghetti; cook -- reserve
                        the water

Preparation:

Sauté‚onions in oil. Add tomatoes, 1/4 of the basil and pepper flakes. Simmer about 45 minutes. Add butter and remaining basil. If sauce is too thick, add some pasta cooking water. Serve over pasta. Source: David Rosengarten, Taste.