The protein style burger is defined entirely by the substitution it makes: the bun is gone, replaced by a wrap of cold iceberg lettuce, and that single swap changes the structural problem of the whole sandwich. A bun absorbs juice, holds heat, and gives the hands a firm grip. Lettuce does none of that. It is cold, wet, and weak, so removing the bread does not simplify the burger, it forces every other component to compensate for a carrier that contributes nothing structural and actively works against the build.
The craft is in managing a build that has no absorbent layer. The patty is the same thin, hot, griddle-seared beef the bunned version uses, but here it sheds its juice and rendered fat directly into the lettuce and out the bottom, so the meat is often blotted and the build is assembled to be eaten immediately, before the wrap goes limp and the juice runs through. The cheese is melted onto the patty on the steel as usual, doing double duty as a partial seal that slows the bleed since there is no bread to catch it. The spread, the tangy pink pickle-flecked sauce, the tomato, and the griddled or raw onion are layered against the patty rather than the leaf, because the leaf cannot take moisture and hold. The lettuce itself is leafed into a doubled, cupped wrap, chosen for the one thing it does well: a crisp, cold, snapping counter to a hot fatty patty, which is the same cool-and-crunch job a pickle does on a standard build, here promoted to the entire carrier. The sandwich is held in paper and eaten fast and over a tray, because structurally it is always on the edge of failing.
The variations are the rest of the secret-menu grammar it lives inside. A double stacks two patties and forces the lettuce wrap to contain twice the juice it already cannot hold. The same no-bun swap migrates onto other chain burgers as a known low-carb modification, and a mustard-cooked patty can be ordered inside the wrap. Each is a single deliberate change on a fixed frame and belongs in its own article rather than being crowded in here.