Clean, wash and drain the sugar snap peas. Peel and finely chop the onion. Heat the fat in a saucepan and sauté the onion and mangetouts. Add stock, bring to the boil, cover and simmer for 8-10 minutes.
Put the pasta in plenty of boiling salted water and cook al dente for about 10 minutes, drain. Lift the sugar snap peas out of the stock with a skimmer, stir in the mascarpone and sauce thickener and bring to the boil again briefly.
Mix the egg yolks with a little hot sauce, stir into the remaining sauce and season with salt and pepper. Mix the pasta, snow peas and sauce, place on plates and arrange the Parma ham on top.
Season with pepper from the mill and serve garnished with parsley.