I just used a beaten egg, with thyme and salt and pepper. Fry up your bacon, pancetta whatever in some spray light, beat egg ( i make it for 2 adults and 2 kids (6 ,4) and i use 2 eggs, beat them up in a separate bowl. Drain pasta, add to frying pan with bacon etc then add egg and stir continuously and fry for about 30 secs on a high heat, then take off heat and add parmasean if using. You don't want scramble egg so do it quickly and on a high heat is the key!!! Good luck.. 2 medium eggs is only 4 pp and I do this all the time,works out fine. Also if you don't want to, you could use maybe a soft cream light cheese, i get one in aldi, much cheaper than philly!!