Add cream and cook stirring occasionally until sauce is thick
Cook pasta according to instructions
Drain pasta reserving a couple of tablespoons of the cooking water
Add butter to pasta and stir though until coating pasta
Add egg yolks to pasta and again stir till coated (the eggs are not raw at this point as they have used the heat in the pasta to cook onto it making it silky)
Place on serving platter and pour sauce over
Serve and allow guests to grate fresh Parmesan over. Goes very nicely with some more of that wine