My cousin is a food editor in New York and also loves to cook. He posted up this recipe before for "The Most Talked-About Buttery Tomato Pasta Recipe Ever". I've made it many times and can confirm it's freaking tasty. Below is a link to his article with the recipe, and I've cut and paste it below.
http://www.gilttaste.com/stories/4572-the-most-talked-about-buttery-tomato-pasta-recipe-ever
Buttered Onion Tomato Pasta
Serves 4 as a main course, 6 as a starter
5 tablespoons butter
1 medium onion, peeled, cut in half along the equator
1 28-ounce can tomatoes with juice (there are hardly any ingredients in this sauce, so show off your good tomatoes!)
1 pound dried pasta
For the accompanying “salad”
¼ medium red onion
1 fistful soft herbs – parsley, basil, or even mint or cilantro
Mild vinegar, to taste
Salt, to taste
1. In a medium saucepan, melt the butter over medium low heat and add the onion halves, cut-side down.
2. Crush the tomatoes by hand in a mixing bowl, and don’t squirt them all over yourself. If the tomatoes are really firm and not really coming apart, chop them up or puree them. (Or puree them after the sauce is cooked if necessary, which I prefer because it also re-emulsifies the butter.) Listen to the onion start to sizzle and breathe deep, thinking, “Oh yeah, that’s what that smells like.” Scatter the crushed tomatoes around the onion, and when they’re all in there, pour in the tomato juice.
3. Turn the heat up, bringing the liquid up to simmer, then turn it down so that it cooks slowly, uncovered, with very gentle but persistent bubbles. Season lightly with salt and simmer 45 minutes, stirring occasionally.
4. While the sauce is cooking, slice the red onion as thin as you can, season it with a pinch of salt and a splash of vinegar, just enough to moisten it. Roughly chop the herbs, but don’t combine them with the onion. Look in the saucepan. As the sauce cooks, the butter will emulsify in, turning the red into more of a deep pink. After 45 minutes, the sauce should have reduced by about half, the butter will be threatening to break back out and float back to the top. The flavor will round out and deepen; and it should be sweet, tart, and buttery in equal measure.
5. Bring a large pot of generously salted water to a boil and cook the pasta ‘til al dente. As it cooks, season the sauce with salt (and maybe a pinch of sugar) to taste. Combine the chopped herbs with the red onion. Toss the cooked pasta in the sauce and serve, with a small pinch of onion salad on top or on the side. Go light on the onion salad, since you want to be able to have bites that are just pasta and sauce to revel in its loveliness.