a U.S. Girl Scout word: ‘s’more’

Originally a U.S. Girl Scout noun, s’more, also smore, denotes a dessert or snack consisting of toasted marshmallows and chocolate sandwiched between graham crackers, typically served outdoors, with the marshmallows toasted over coals or a campfire.

The earliest occurrence that I have found is from Campfire Cookery, by ‘Brown Owl’ 1, published in the Girl Scouts Department of The Birmingham News (Birmingham, Alabama) of Sunday 29th April 1928:

Smores
Two large graham crackers
One half plain Hersheys 2
Two marshmallows.
Toast marshmallows and make sandwich of crackers, Hersheys 2 and marshmallows. A grand dessert!

1 The adult leader in charge of a Brownie unit is usually called ‘Brown Owl’. The noun Brownie designates either a member of the junior branch of the Girl Scouts in the United States, for girls aged between about six and eight—cf. origin of ‘Brownie’ (Girl Scout or Girl Guide) and a hypothesis as to the origin of ‘brownie point’.
2 The U.S. chocolatier, businessman and philanthropist Milton Snavely Hershey (1857-1945) founded the Hershey Chocolate Company at Lancaster, Pennsylvania, in 1894.

The word s’more represents a rapid pronunciation of some more—as, for example, in this advertisement for Van Duzer’s Extracts, published in The Minneapolis Morning Tribune (Minneapolis, Minnesota) of Friday 28th May 1926:

S’More Dessert Mother.. Please!

advertisement for Van Duzer’s Extracts - The Minneapolis Morning Tribune (Minneapolis, Minnesota) - 28 May 1926

The earliest occurrence that I have found of some more in the sense of a U.S. Girl Scout dessert or snack is from one of the Scout Troop Letters published in the Girl Scouts Department of The Birmingham News (Birmingham, Alabama) of Sunday 30th August 1925:

I’ll give you the recipe for “Some Mores.” First, buy the biggest Hershey chocolate you can find. Second, buy a box of good graham crackers. Third, buy a box of marshmallows. Fourth, toast four marshmallows. Fifth, put them on a cracker. Sixth, put four squares of chocolate on top. Seventh, another cracker on top of that. Eighth, now Eat! Yum! Yum!
Doesn’t that make your mouth water.

However, marshmallow roast, denoting a gathering at which marshmallows are roasted and eaten, usually around an open fire or barbecue, predates Girl Scouts. The earliest occurrence that I have found is from The Detroit Free Press (Detroit, Michigan) of Sunday 8th December 1889:

What is a marshmallow roast? Well, it is a sort of social diversion that sprang into existence during the summer season at some of the more quiet northern resorts. Just how it originated “you nor I nor nobody knows,” but it became a very popular amusement with the young maidens and their laddies who delighted in strolling about after nightfall and holding high carnival in groups of ten or twenty. The outlay was very simple: plenty of marshmallows and a huge bonfire, around which, on improvised seats of logs, a gay party would seat themselves, holding over the bright coals on sharp-pointed twigs—gathered from some neighboring oak or pine—a marshmallow. Then the merriment began, and many an interesting story was told while the candies turned a rich warm amber, an occasional “Oh” and “Ah” breaking forth as the creamy curd was transferred from the twig to the mouth.
No pleasanter form of amusement during the long winter evenings can be imagined than a party of six or seven seated around the glowing embers of a grate fire toasting on pine sticks—which may be found at the florist’s for that purpose—the large, luscious, sugar-sprinkled marshmallow, each relating in his turn some pleasant anecdote in which he figures “in his own proper person.”
“It is quite a nice little trick,” said a devotee of the marshmallow roast, to toast the candies properly. “In the first place, they must be the very best of their kind, those coming in pound boxes at sixty cents each being usually purchased. They take the color evenly and dissolve into a delicious sweetness, while the cheaper grades will burn and crackle and prove anything but toothsome.”
The marshmallow, which has long been a favorite confection, but whose sugar-dusted coating has prevented its use by dainty gloved fingers, has been recently treated by a diplomatic confectioner, who appears to know the longings of the female stomach, to an outside crust of chocolate which not only adds to its goodness but is warranted not to injure the most delicate glove. So the idealized marshmallow has taken the place of the bonboniere drop and become the sweet of the matinee.