Bring a large pot of salted water to a boil.

Heat the olive oil in a large pan over medium-high heat, add the sausage in small, meatball-sized chunks and cook until browned and cooked through, about 7–9 minutes. Transfer to a plate, leaving about 1 tablespoon of fat in the pan.

Lower the heat to medium, add the shallot and cook for 2 minutes then add the garlic and crushed red pepper - cook for another minute.

Stir in the tomato paste and cook for 1–2 minutes, until it darkens slightly. Add the wine, scrape up the browned bits and simmer uncovered for 5 minutes. The goal is to reduce the wine before adding the pasta, then finish the spaghetti in it. You want a savory, wine-rich sauce that clings, rather than a puddle of wine under your noodles.

Meanwhile, cook the spaghetti for 4 minutes less than its package directs - hang on to about a cup and a half of the pasta water before draining.

Add the spaghetti to the wine sauce along with ½ cup pasta water. Simmer briskly, tossing frequently, until the pasta is al dente, about 4–6 minutes. Add more pasta water a little at a time as needed so the spaghetti keeps cooking without the pan drying out.

Kill the heat under the pan, and put in the sausage, the butter and Parmesan - tossing well to mix, adding another splash of pasta water if needed to make the sauce glossy and loose enough to coat the spaghetti.

Serve with extra Parmesan.