Mix the breadcrumbs and Parmigiano cheese together in a bowl.
Add a pinch of salt
Add the grated nutmeg or lemon rind (as desired).
Beat the eggs and add them to the bread and cheese mixture.
Mix the ingredients together (preferrably with your hands) until the dough becomes quite elastic and compact. If it is too wet add more breadcrumbs. If too dry you can add some of the stock or broth you plan to cook the passatelli in.
Roll the dough into a large ball, wrap it in clingfilm and leave it to 'rest' at room temperature for at least 2 hours.
Bring your broth or stock to the boil
When you are ready to cook the passatelli, remove the clingfilm and place the dough on a floured surface.
Take large pieces of the dough and press through the passatelli iron. As the passatelli come out of the press you will have to use a knife to remove them.
You can drop them straight into the boiling broth/stock or onto a previously floured surface and then add them to the broth/stock after they are all made.
Allow them to cook until they all rise to the surface (approx 5 minutes)
If you are serving them in broth, serve immediately.