Heat large non-stick fry pan over high heat. Place mushrooms, onion and garlic in a food processor. Process to form a thick paste. Add mushroom mixture to the hot pan, squeeze sausage meat out of the casings and cook for 6 minutes.
Add tomato paste to mixture and cook for a further 4 minutes. Reduce heat, add tomato passata and simmer for a further 2 minutes.
Meanwhile bring a large pot of water to the boil and cook pasta to packet instructions. Strain and set aside.
Add pasta to sauce and serve with basil leaves and shavings of Parmesan.