Bring a saucepan to the boil with salted water, add tagliatelle, and cook until tender with a bite at the centre (al dente), about 5 minutes. You should be able to make the sauce while the pasta is cooking.
Heat a pan with the olive oil. While that's heating, slice up the Parma ham.
Add the Parma ham to the pan. After 2 or 3 minutes put in the cream, salt and pepper, and when it starts bubbling add the white wine and stir.
Drain and add the pasta to the sauce and stir together, serve with Parmesan.
With the egg there is two ways to do this: the traditional way is to crack the egg open, remove the egg white and serve the yolk in half the shell on top of the pasta, then when going to eat, you tip the egg yolk out the shell and mix in. If you prefer you can just mix the egg yolk in when stirring the tagliatelle into the sauce.
For Northern Italian add peas and / or mushrooms when the cream is bubbling.