Burger King is testing a vegetarian Whopper made with Impossible Burger

Jane Lanhee Lee | Reuters

Impossible Foods product development associate scientist Kyle Okada measures plant-based burgers tailor-made for Burger King at a facility in Redwood City, California, U.S. on March 26, 2019.

Burger King is testing a vegetarian version of its Whopper that uses an Impossible Burger for its patties, becoming the first national fast food chain to sell the plant-based burger.

The Restaurant Brands International subsidiary is offering the Impossible Whopper at 59 of its St. Louis locations. The burger chain already sells veggie patties made by Kellogg’s vegetarian brand, Morningstar Farms.

Silicon Valley-based Impossible Foods genetically engineers heme, a protein that makes the vegetarian-friendly burger taste like meat. The ingredient is also responsible for giving the patty red juices that make it look like it’s bleeding just like any other piece of beef.

The Impossible Burger is already sold in more than 5,000 restaurants, but if Burger King takes it nationwide, it would more than double its footprint.

Red Robin has also joined the ranks of fast casual restaurants bringing the plant-based burger to its 570 stores. Before Burger King’s announcement, Midwestern chain White Castle was the only fast food restaurant to sell the Impossible Burger at its nearly 400 locations. Meanwhile, Carl’s Jr. launched a plant-based burger made in partnership with Impossible Food’s main competitor, Beyond Meat.