Using Store-Bought Pasta--cook according to package directions.

Making your own pasta--mix the flour and the eggs to form a dough. Turn out on a well-floured surface and knead for 2 minutes. Cover in plastic and let it rest for 30 minutes. Then run through a pasta roller to #4 or #5 depending on desired thickness. Then run through the fettuccine cutter, dust with additional flour so it doesn't stick together then set aside (or place in the refrigerator). Use the same cooking method as the kind you buy in the box except fresh pasta will only take about 3 minutes to cook al dente.

For the sauce--melt the butter over medium-low heat. Stir in the cream, Parmesan, Romano, salt, pepper and nutmeg then heat through. Lightly beat egg yolk then whisk in a couple of tablespoons of the hot liquid then whisk the egg yolk mixture into hot liquid. Cook and stir until the mixture reaches 160F/70C or until it coats the back of a spoon. Cover and keep warm while cooking pasta.

Drain the cooked pasta and combine it with the sauce. You can add additional Parmesan or Romano if you wish. Sprinkle with the parsley and serve.