Hamburger with Borettane Onions and Fontina

Onion lover? A hamburger enriched with Zuccato Borettane Onions in Balsamic Vinegar of Modena, Fontina and barbecue sauce. The onions add a sweet-and-sour note to the filling and fit easily into the preparation without extra steps. A simple idea for personalising a homemade hamburger with an alternative to more usual onions.