Fresh San Marzano Tomato Sauce

Heat the extra virgin olive oil in a large Dutch oven or heavy-bottomed pot over medium-low heat. Add the finely diced onion and cook for 4–5 minutes until soft and translucent.
Add the halved fresh San Marzano tomatoes directly to the pot. Cover and cook over low to medium-low heat for 20–25 minutes, stirring occasionally, until very soft and juicy.
Use kitchen tongs to carefully remove and discard the loosened tomato skins from the pot.
Add the minced garlic, dried oregano (or Italian seasoning), kosher salt, black pepper, and fresh basil stems. Stir everything together.
Mash the tomatoes with a potato masher directly in the pot until saucy while leaving a rustic texture.
Simmer uncovered over low heat for another 20–30 minutes, stirring occasionally, until the sauce has thickened and concentrated. Remove and discard the basil stems.
Meanwhile, bring a large pot of salted water to a boil and cook pasta according to package instructions until al dente. Reserve about 1 cup pasta water before draining.
Toss the cooked pasta with the tomato sauce over low heat for 1–2 minutes, adding a splash of reserved pasta water if needed to coat the noodles.
Serve immediately garnished with plenty of fresh basil leaves and freshly grated Parmigiano-Reggiano (or vegan Parmesan).