Cook the pasta in a pot of boiling and salted water according to package directions.
Meanwhile, fry the pancetta, add arugula to it in the last minute just to wilt it. Set aside.
Beat an egg with a fork and add grated parmesan to it, mix everything.
Drain the pasta, reserving 1/2 cup of water and add pasta to the pan with pancetta and arugula. Mix everything over low heat with a spoonful of cream and a pinch of salt just to coat.
Take your pasta off the heat and mix in the egg and cheese mixture tossing the pasta gently, add a splash of reserved water to keep things slightly runny but it shouldn't be swimming in sauce.
Serve with more freshly grated parmesan cheese.