Step 1

Place the olive oil in a medium-sized saucepan with the onions and sauté on medium until pale gold — you’re not trying to brown the onions here; you just want to sweat the onions. Add the garlic and cook just a few seconds until you smell its aroma. Add the parsley, stir once or twice, and then add the wine. Let it simmer for a couple of minutes until the alcohol smell dissipates.

Step 2

Add the tomatoes, the crushed chili flakes and a generous pinch of salt, and cook at a steady simmer, until the fat begins to separate from the sauce (see note below*), about 20 minutes.

Step 3

Meanwhile, brown the sausage in a large skillet until cooked through.

Step 4

Bring a large pot of water to a boil. Cook your pasta al dente. Drain, reserving some of the pasta cooking liquid only if you’ve made the sauce in advance and are reheating it to toss with pasta.

Step 5

Place pasta in a large serving bowl. Toss with enough sauce to coat. Fold in sausage (if using). Sprinkle with some more parsley (optional). Pass cheese on the side.