Six decades after its founding, the Italian American Club Restaurant of Las Vegas is still going strong. Even on weeknights, singers on stage will serenade a dining room filled with snazzily-dressed eaters. The menu is long on classic Italian cuisine, with hits like chicken parm, veal Marsala, and fresh pastas. This is not a lunch joint: Portions are large, there are no sandwiches, and they’re open only for dinner. Frank Sinatra was a longtime member of the Italian American Club, and legend has it that his donation of a Cadillac helped…