The snack made from graham cracker cookies, marshmallow filling, and a flavored coating is a Moon Pie.
Moon Pies were introduced by Chattanooga Bakery in Tennessee in 1917. Company lore says a traveling salesman asked a Kentucky coal miner what sort of snack he wanted; the miner reportedly requested graham crackers and marshmallow, “as big as the moon.” The story helped inspire the name, although it is best treated as brand folklore rather than independently documented history.
A traditional Moon Pie has two round graham crackers surrounding marshmallow and an outer coating. Chocolate is the best-known flavor, but banana, vanilla, strawberry, salted caramel, and seasonal varieties have also been sold. Double-decker versions add a third cookie and another marshmallow layer.
Moon Pies are especially associated with the American South and are often paired with RC Cola. They are sometimes confused with Mallomars, Scooter Pies, or Wagon Wheels, which are related marshmallow-cookie treats made by different companies.