Drain the pasta, reserving a little of the
cooking water, then return to the pan.
Tip in the cooked ham. Mix together the
lemon juice, egg yolks and crème fraîche,
then add this to the pan along with the
basil and Parmesan. Mix in with tongs,
adding a little of the cooking water, if
needed, to make a creamy sauce that
coats the pasta. Serve with extra
Parmesan grated over the top, if you like.