Hamburger with grilled Parmigiano Reggiano and raw vegetables.

Cook the burgers on a grill. Cut Parmigiano Reggiano into slices of about 0.5 cm thickness, place them on a hot griddle and cook until the cheese starts melting. Slice onion and tomato. Cut the bun in half and spread each piece with mustard, then form the layers with lettuce, beef burger, grilled Parmigiano Reggiano, onion and sliced tomato.