6 tablespoons butter
A few leaves fresh basil, torn
1 large clove garlic, grated or pasted, optional
1 small onion, halved
One 28-to-32-ounce can crushed Italian tomatoes
1 pound spaghetti
Freshly grated Parmigiano-Reggiano
Using crushed tomatoes rather than breaking down whole tomatoes cuts the cook time of this sauce in half.