For the pasta:
Blanch the pasta in boiling salted water until tender and then drain, reserving about 20ml of the water (this will help to bind the sauce later on). Toss through with a splash of olive oil but do not refresh. For the sauce:
Grate the parmesan. In a bowl, whisk both cheeses together with the eggs. Then season with a pinch of salt and pepper.
Cut the pancetta into lardons and fry in a pan with the butter until crispy. Using a piece of kitchen paper wipe away any unwanted fat from the pan then add the pasta along with the pasta stock to the lardons. Remove from the heat and pour the egg and cheese mix into the pasta, using tongs to mix around until evenly distributed. Finish with chopped parsley.
Twist into a bowl using tongs.