Add the penne to lots of salted boiling water and cook for 6 minutes, then add the asparagus for a further 2/3 minutes until they are tender but still have a little bite.
Whisk the cream with the egg yolks; add half the Parmesan and season with salt and lots of freshly ground black pepper.
Fry the pancetta in a dash of olive oil, add the rosemary sprigs and cook until slightly crisp.
Toss in the parsley, asparagus and penne and toss with the egg yolk and cream sauce (the heat of the pasta will cook the sauce).
Serve with the rest of the Parmesan sprinkled over. Enjoy.