Cat the unions in slices and cook them on a slow fire, until they are golden, on a pan with a little oil.
Beat the eggs in a bowl, then add the onions, the parmigiano and some salt.
Put the mix in the pan you eat al ready used and cook it with oil.
After a 10 minutes turn the omelette, usings a pan’s lid, and let it cook again, always on a not too strong fire.
Wen the omelette are coked, put it on blotting-paper.
Serve hot, in slices, with some salad.