In a large skillet, heat olive oil over medium heat until shimmering. Add shallots, season lightly with salt, and cook, stirring frequently with a wooden spoon, until shallots are softened but not browned, 5 to 7 minutes.

Add 'nduja and cook, mashing it into the oil with a wooden spoon, until melted, about 2 minutes. Add passata; make sure to use up all of the tomato in the bottle by adding ¼ cup (60ml) water to the empty bottle, screwing on the lid, shaking the contents, and then adding tomato-water mixture to the skillet. Bring to a simmer, season lightly with salt, and cook, stirring occasionally, until the sauce is slightly thickened, 12 to 15 minutes.

Meanwhile, in a pot of salted boiling water, cook pasta until just softened on the exterior, but well shy of al dente, and still uncooked in the center (about 3 minutes less than the package directs). Using a spider skimmer, transfer pasta to sauce, along with ½ cup (120ml) pasta cooking water. Alternatively, drain pasta using a colander or fine-mesh strainer, making sure to reserve at least 1 cup (240ml) pasta cooking water.

Increase heat to high and cook, stirring and tossing rapidly, until pasta is al dente and sauce is thickened and coats noodles, about 2 minutes, adding more pasta cooking water in ¼ cup (60ml) increments as needed. Remove from heat, and season with salt to taste. Serve immediately with grated cheese on top.