Gone are the days, it seems, when the veggie burger was almost a source of shame. Sure, some restaurants fixed their own, from scratch, but many others served a dry mass-produced patty — one that might well have been made of natural ingredients like mushrooms and oats and black beans and brown rice, but which nevertheless had been gathering ice crystals in the freezer for an unknown period of time.

Tal Ronnen, 36, the author of the 2009 cookbook “The Conscious Cook,” has seen the frozen versions, too, gradually improve in the ensuing years. (Lately he has collaborated with Gardein in creating the food company’s new Ultimate Beefless Burger patties.) “When I first started eating this way, they came in a box,” said Mr. Ronnen, a chef who signed on this month to create vegan choices for the restaurants in all of the Wynn and Encore hotels in Las Vegas. “You had to add water to it. It was embarrassing to eat it around anyone. Imagine showing up to a backyard barbecue with a box and saying, ‘Hey, can I have a little bit of water to form a veggie burger?’ ”

If there is a primary reason they are improving, it comes back to the force that drives just about anything in the marketplace: demand. According to Mintel, a market research firm, there was a 26 percent increase in menu items labeled vegetarian or vegan between the last quarter of 2008 and the same quarter in 2010.

With more and more people pledging themselves to vegan and vegetarian modes of dining, it seems self-defeating for restaurants to ignore them — or to pretend that those diners will be satisfied with yet another droopy grilled-vegetable platter. The signs are clear enough that two high priests of the global burger gospel, Burger King and McDonald’s, have for years given veggie burgers a run, although only Burger King currently has one on menus in the United States.

“It is really awesome to see a lot of places starting to make their own patties from scratch, instead of simply stockpiling premade ones in the freezer,” said Joni Newman, the author of a cookbook, “The Best Veggie Burgers on the Planet,” which Fair Winds Press is to publish in May.

But with thousands of flora-based recipes in the world, why the compulsive return to the burger genre? “There’s something really satisfying about a hand-held food that’s served on a bun,” said Lukas Volger, the author of “Veggie Burgers Every Which Way,” a cookbook that was published last year. The patty-bun-condiments format of a burger holds sway over us the same way the dependable verse-chorus-bridge structure of a perfect three-minute pop song does.

That said, there is vigorous debate over how closely a veggie burger should ape the look and taste of beef.