NYT Cooking: Homemade marinara is almost as fast and tastes immeasurably better than even the best supermarket sauce — and it's made with basic pantry ingredients. All the tricks to a bright red, lively-tasting sauce, made just as it is in the south of Italy (no butter, no onions) are in this recipe. Use a skillet instead of the usual saucepan: the water evaporates quickly, so the tomatoes are just cooked thro