1) Start by peeling and slicing the onions.
2) Wash, dry, and mince the sage.
3) In a pan, melt the butter with the oil then add the sliced onions and add the water.
4) unisci le cipolle affettate e aggiungi un goccio d’acqua,
5) Continue cooking over low heat for 5 minutes, then add the minced sage and the white wine vinegar.
6) Continue to cook for another 5 minutes until the onions are dried.
7) Place the burgers in the pan with the onions and cook them for 5 minutes on each side. Cut the sandwiches in two and lightly toast them in a separate pan.
8) When the Burgers are ready, prepare the sandwiches by placing a good portion of onions on each base, placing the burger on top, and closing with the other half.