Green’s Dictionary of Slang

(US) a dish of pork (belly) and baked beans; frankfurters and baked beans [the baked beans resemble stars and the pork belly/frankfurters resemble stripes].

1883		Daily News 13 July in Ware (1909) 233/1: New Englanders are proud of their national dish of pork and beans, eaten cold on Sundays in Boston, and derisively called ‘stars and stripes’ in New York.
1885		North Amer. Rev. Nov. 434: In the slang of the New York common restaurant waiters a plate of ham and beans is known as ‘stars and stripes’.
1896		Salt Lake Herald (Salt Lake City) 13 Jan. 8/3: The first guest ordered liver and bacon and a shout of ‘Stars and Stripes’ elicited the answer from the cook.
1917		J.A. Moss Officers’ Manual 485: Stars and Stripes, beans [DA].
1952		J. Jones From Here to Eternity (1998) 187: On this day there had been the usual Preem dinner menu of canned franks and canned baked beans, sometimes called ‘Stars and Stripes’.