Mound the semola on a clean board, make a well and pour in 190 ml lukewarm water. Mix with a fork, then knead by hand for 10 minutes until the dough is smooth, firm and slightly tacky. If it feels crumbly or cracks when pressed, knead in water a teaspoon at a time, because dry dough splits when wrapped. Cover and rest for 30 minutes.

Cut off a quarter of the dough and keep the rest wrapped. Roll the piece into a rope about 8 mm thick and cut it into 4 cm lengths.

Lay the ferretto across one piece at a slight angle, press to flatten, then roll it back and forth under your palm so the dough wraps the rod in a spiral. Slide the fusilli off and set it on a semola-dusted sheet pan. Repeat with the remaining dough, which takes 30 to 40 minutes the first time.

Pour 3 liters of water into a 5 L / 5-quart pot, add the salt, cover and bring to a boil while you make the sauce. In a 28 cm / 11-inch deep skillet, warm the olive oil over medium heat. Cook the onion for 5 minutes until soft and translucent, then add the garlic for 30 seconds.

Add the nduja in spoonfuls and mash it into the oil with a wooden spoon. Cook for 2 to 3 minutes at medium heat until it melts and the oil turns brick red.

Crush the tomatoes by hand into the skillet and pour in their juice. Simmer gently for about 14 minutes, stirring now and then, until the sauce coats the back of a spoon and oil pools at the edges.

When the sauce has simmered for 5 minutes, drop the fusilli into the boiling water. Cook for 8 to 10 minutes, tasting at 8, until tender with a slight chew. Scoop out a mug of pasta water before you drain.

Lift the pasta with a spider straight into the sauce, add 60 ml pasta water and toss over medium heat for 1 minute until the sauce turns glossy and clings to the spirals. Add a splash more water if it looks tight. Stir in the basil and half the pecorino, then serve at once with the rest of the pecorino on top.