The gatsby is a huge sandwich: a long roll, split lengthwise and filled with slap chips — the thick, soft fries seasoned with vinegar — a meat or fish, salad and sauce. The most popular fillings are masala-seasoned steak, chicken, sausage, mortadella, fried calamari and fish; the sauce is typically achar, the spicy Indian-origin pickle, or piri‑piri. Topped with a fried egg and cheese, it becomes a complete gatsby.
The most commonly told origin story is about the owner of a fried-fish shop in Athlone, a neighborhood in the Cape Flats, the plain southeast of central Cape Town. According to the vendor himself, one night in the 1970s, with no fish to serve to workers he had hired, he filled a round roll with fries, mortadella and achar. One of the men allegedly called the sandwich a "Gatsby smash," referring to the film The Great Gatsby playing at a neighborhood cinema. The city’s official tourism body gives the year 1974; news reports with the vendor mention 1976. Another version says Cape Flats residents were already stuffing long rolls with leftovers to feed many people.
Over time the round roll was replaced by the long one, easier to divide. The gatsby spread to the city’s snack bars from the late 1980s and became part of life in the Cape Flats and the city center.
The custom is to buy a whole gatsby for a group. The seller asks how many pieces to cut it into, and each person takes theirs. The middle piece, with the most filling, is the most sought after.