> It's a fried patty. Even for the meat kind, there's essentially no resemblance to the original animal.

Sure, but I would say that means vegetarian cuisine has less reason to emulate the form. It's entirely arbitrary. The point of eating a burger is that it's yet another convenient way of getting meat on a bun. (cf. fast-food places describing them as "sandwiches".) The social ritual of eating burgers with friends isn't about seeing the patty extend past the edges of the bun and thinking about the cow. It's about everyone holding something they'll enjoy eating, conveniently wrapped and portable, and chowing down. The burger is recognizable as a "burger" (as distinct from a wrap or a traditional sandwich) from the bun before it's recognizable from the contents. (Which is part of why the marketplace had no problem accepting chicken burgers.)

So anything that holds the vegetables together and keeps them inside a bun ought to work just fine. If our prospective new vegetarian wants the burger filling to taste like (or match texture etc.) a beef patty, that's a personal issue.