Pasta with Tomato, Onion and Butter

Ingredients

1 pound spaghetti

Kosher salt and ground black pepper

4 tablespoons salted butter, cut into 1-tablespoon pieces, divided

1 small yellow onion, chopped

6-ounce can tomato paste

1 tablespoon balsamic vinegar OR white balsamic vinegar

1 ounce Parmesan cheese, finely grated (½ cup), plus more to serve

Optional garnish: Chopped fresh basil

Directions

In a large pot, bring 4 quarts water to a boil. Add the pasta and 1 tablespoon salt, then cook, stirring occasionally, until al dente. Reserve 2 cups of the cooking water, then drain; set aside.

In the same pot over medium, melt 2 tablespoons butter. Add the onion, reduce to low, cover and cook, stirring occasionally, until the onion has softened, 12 to 14 minutes.

Add the tomato paste, ½ teaspoon pepper and 1½ cups of the reserved cooking water, then whisk until smooth. Add the pasta, the remaining 2 tablespoons butter and the vinegar. Using tongs, toss until the sauce clings to the pasta, the pasta is heated through and the butter is melted, adding more cooking water if needed so the noodles are lightly sauced.

Off heat, toss in the Parmesan, then taste and season with salt and pepper. Serve sprinkled with additional Parmesan.

Notes

Marcella Hazan’s famous tomato sauce with onion and butter, from her book “The Essentials of Classic Italian Cooking,” transforms three simple ingredients into a luscious sauce. Our pantry-focused version replaces the fresh tomatoes with a can of tomato paste to create a dish that can be on the table in minutes. To enhance the sweetness and umami, we finish the sauce with a splash of balsamic vinegar and nutty Parmesan cheese. If you don’t have spaghetti, use another type of pasta, such as fettuccine or linguine. Fresh basil, though an optional garnish, is a great addition; if you have it on hand, toss some into the pasta just before serving.