White Castle Expands the Impossible Slider to All Store Menus

Back in April, the fast food chain White Castle added the Impossible Slider, a plant-based mini burger to the menus of 140 of its chains in New York, New Jersey, and Chicago area.

In partnership with Impossible Foods, the chain has announced that it will be expanding the menu item nationwide.

The Impossible Burger has become wildly popular among vegetarians and flexitarians. The veggie burger that looks so much like the traditional beef burger that it even bleeds.

The ingredient soy leghemoglobin, which causes the burger to "bleed," is made from soybean plants. The ingredient got regulatory pushback from the Food and Drug Administration (F.D.A.) last August but was officially approved two months ago.

Impossible Foods, which has garnered over $250 million in investment, aims to bring veggie burgers to the fast food lovin' masses.

“White Castle’s model has been often imitated but never duplicated -- an impressive feat in the hypercompetitive fast-food sector,” said Patrick O. Brown, Impossible Foods’ Founder in the press release from April announcing the companies' partnership. “We look forward to working closely with White Castle, and together learning how to popularize plant-based meat with mainstream burger lovers.”

Evidently' White Castle's Impossible Slider test was well-received.

"Our Cravers definitely developed a hunger for the Impossible Slider," said Lisa Ingram, White Castle's CEO. "Sales easily exceeded our expectations."

The slider is topped with cheddar cheese, pickles, onion, and the White Castle signature 2-inch-squared bun.

But the Impossible Burger isn't the only veggie burger that "bleeds." Impossible Food's biggest rival, Beyond Meat also has a burger that bleeds, but this is merely just beet juice. Beyond Meat was the first plant-based burger to be sold in the meat section of grocery stores.

The good news is that there appears to be room for both of these plant-based companies. Plant-based consumption is up over 300 percent over the last year.

Learn all about the plant-based movement in the video below.

Read more about White Castle rolling out the Impossible Slider nationwide at "CNBC" now.