Arby's Slow-Cooks Its First Burger

"We have the meats" is Arby's slogan, and the fast-food chain certainly has branched into numerous animal proteins besides roast beef. But never a burger … until now.

Arby's on May 23 announced a limited-time Deluxe Wagyu Steakhouse Burger. It's actually a blend of 52 percent American Wagyu (as opposed to Japanese Wagyu) beef and 48 percent traditional ground beef, according to a Yahoo News story. It comes topped with American cheese, shredded lettuce, tomato, pickles, red onion and a special burger sauce on a toasted buttery brioche bun. Price is $5.99.

This marks the first burger in the chain's 58-year history. Reports say it's a hefty 6.4 oz. – 50% larger than a quarter-pound burger – and 715 calories, more than half of them from fat. Sodium is 1,567mg. Rather than the grill or the griddle, it's cooked sous vide-style – in vacuum-sealed bags in a hot water bath. Arby's said the result is "medium-well with a hint of pink."

No word on who supplies the burger. The test runs May 23 to July 31 "at participating U.S. locations while supplies last."