Bring a large pan of salted water to a boil and cook the pasta for 8-10 minutes or according to packet instructions. When the pasta is al dente, drain, reserving a tbsp of cooking liquid to add to the sauce.
Meanwhile, heat the oil over medium heat and add the onions. Cook for 5-6 minutes until the onions are soft and begin to brown. Stir in the garlic and ‘Nduja and cook for a further minute. Deglaze the pan with the reserved pasta water and add the tomato passata. Cook for an additional 2 minutes to allow the flavours to infuse.
Toss the drained pasta with the sauce and stir in the torn basil. Season to taste.
Serve topped with freshly grated parmesan and chopped parsley.
