Croque Monsieur with Truffle Sauce (Tartufata)

Slice the bread and spread the butter on top of each slice. Sprinkle with grated Emmental cheese, add a slice of cooked ham and a slice of Comté or Guyère cheese. Spread a tablespoon of tartufata sauce, again grated cheese and close.
Cover it in cling film and keep in the fridge so that the bread can soak up the fragrance of the truffle.
Broil in the oven (grill) or in a pan with a little butter.

Variation: You can also add quail eggs cooked in a frying pan over a low heat, to make a kind of croque-madame revisited.