Wash the onions, peel them and slice them. In a frying pan warm the oil and stir-fry the onions till lightly soft BALSAMOSABA® 3.
Cook till the onions are well soaked in vinegar.
Adjust with salt and pepper and let the onions rest in a bowl with their sauce for about half an hour.
Whisk the eggs in a bowl, add the onions, the grated parmgiano, salt & pepper to taste.
Pour the mixture in an oiled ovenproof dish. Garnish the omelette with sage leaves, arranging them on the surface and taking care of dipping them in the egg mix.
Bake in warm oven at 180°C for about 35 mins.
Serve warm with drops of Traditional balsamic vinegar of Modena 12 years.