Check the amount of fat if is not enough add just a very little oil to fry finely chopped onions too, they must become just golden. Meanwhile prepare the sauce;
4
In a bowl beat the egg yolks with the cream , Pecorino, Parmesan, salt and pepper.
5
When the pasta has cooked and drained by water put it in big bowl, pour in the bacon and onions mix well, add the sauce and mix again with salt and pepper. If you like pepper just abound