Croque monsieur
A croque-monsieur is a ham and cheese (typically gruyère) sandwich, sometimes dipped in beaten egg, then pan-fried in clarified butter or grilled (U.S. broiled), and served hot. It originated in France as a fast-food snack served in cafés and bars. More elaborate versions come coated in a Mornay or Béchamel sauce. When topped with a fried egg the dish is known as a croque-madame.
The origin of the name is uncertain but the first part almost certainly derives from the verb croquer (to crunch, or to munch). Its first recorded appearance on a Parisian café menu was in 1910.