Place the dried porcini mushrooms in warm water and soak for about 20 minutes. Scoop the softened mushrooms out of the water and chop them coarsely. Set aside.
Put a large skillet over a medium flame and heat the oil. Add the onion, portobello mushrooms, porcini and pancetta to the pan. Cook until they onion is soft and the pancetta is crisp, about 5-8 minutes.
Add in the passata and a pinch of salt. Cook for 5 minutes and add in the cream. Bring to a boil and add in the cheese and parsley.
Drop the pasta into salted boiling water and cook until al dente. Drain and add the pasta to the sauce. Cook over medium-high heat for 1-2 minutes. Serve immediately in warm bowls.