Method
- In a large, deep pot or Dutch oven (at least 5-quart capacity), heat the 2 tablespoons olive oil over medium heat until it shimmers slightly, about 1 minute.
- Add the chopped onion and cook for 4 to 5 minutes, stirring occasionally, until softened and translucent but not browned.
- Add the minced garlic and red pepper flakes and cook for 30 seconds, stirring constantly, until fragrant; watch closely since garlic can burn and turn bitter in just a few extra seconds.
- Pour in the crushed tomatoes and vegetable broth, stirring to combine, and bring the mixture to a boil over high heat.
- Once boiling, add the uncooked pasta directly into the pot, along with the dried oregano and 1 teaspoon salt, and stir well so all the pasta is submerged in the liquid.
- Reduce the heat to medium so the mixture simmers steadily but not violently, then cover the pot partially with a lid, leaving a small gap for steam to escape.
- Cook for 12 to 15 minutes, stirring every 2 to 3 minutes with a wooden spoon and scraping the bottom of the pot each time, since the pasta starch will settle and can scorch if left unstirred.
- Check the pasta for doneness at the 12-minute mark by tasting a piece; it should be tender with a slight bite, and the surrounding sauce should look thick and creamy rather than watery, since the pasta absorbs most of the liquid as it cooks.
- If the sauce looks too thick before the pasta is fully tender, stir in an extra 1/4 cup of broth or water and continue simmering; if it looks too soupy once the pasta is done, simmer uncovered for another minute or two to thicken.
- Turn the heat down to low and stir in the heavy cream, mixing until the sauce turns a rich orange-red and looks glossy, about 1 minute.
- Add the shredded mozzarella and grated Parmesan, stirring continuously until both cheeses melt completely into the sauce and no clumps remain.
- Taste the sauce and add a small pinch more salt if needed, keeping in mind the cheeses add saltiness of their own.
- Remove the pot from the heat, let it sit for 2 minutes to thicken slightly, then divide among 4 bowls and top with torn fresh basil.
Tips
Stir often while the pasta simmers in the sauce; because there's less water than a normal pasta pot, the starch concentrates quickly and will stick and burn on the bottom if ignored.
Add the pasta only once the tomato-broth mixture is fully boiling so it starts cooking immediately and doesn't turn mushy from sitting in lukewarm liquid.