Whisk together the eggs, cream and 100g Parmesan cheese in a bowl. Blend thoroughly and set aside.
Cook penne according to packet instructions. Drain pasta, then return it to the pot (off of the heat) and cover to keep warm.
Meanwhile, heat the olive oil over medium heat in a large frying pan; add the onion and cook until transparent, about 8 minutes. Remove onion from the pan and set aside.
Using the same pan, cook the pancetta over medium heat until browned, tossing with nutmeg. Remove pancetta and discard dripping or reserve for another use.
Combine the penne, onion, pancetta, pine nuts, salt and pepper in the same large frying pan over low heat. Slowly stir in the egg-cream mixture, tossing gently over very low heat so the eggs don't scramble. Stir until just heated through. Remove from heat and toss with parsley and remaining Parmesan cheese. Serve immediately.