MIAMI — Burger King is putting a plant-based spin on its signature sandwich with the new Impossible Whopper. The meat-free burger is available at 59 Burger King locations in the St. Louis area as part of an initial test that may lead to a nationwide roll-out, the company said.

To create the new offering, Burger King parent Restaurant Brands Internationals, Inc. partnered with Redwood City, Calif.-based Impossible Foods, manufacturer of the Impossible Burger. The Impossible Whopper features a flame-grilled, plant-based Impossible Burger patty topped with sliced tomatoes, lettuce, mayonnaise, ketchup, pickles and white onions.

The limited-time offer makes Burger King restaurants the first coast-to-coast quick-service restaurant to serve the plant-based meat from Impossible Foods. The company in January unveiled its Impossible Burger 2.0, a new iteration of its burger made with soy protein rather than wheat protein that contains no gluten, animal hormones or antibiotics. Additionally, the new recipe was designed to be steamed, seared or sizzled on slats over an open flame, opening up the possibility for this debut at Burger King, which is known for flame-grilling its burgers.

The Impossible Burger handles, cooks and tastes like ground beef from cows but is made entirely from plants, Impossible Foods said. The burger’s crucial ingredient is leghemoglobin, or “heme," which gives the Impossible Burger its bleeding attribute and creates the flavor in raw and cooked product. Heme reacts with the proteins, amino acids, sugars and vitamins in the blend.

The Impossible Burger generates about 87% fewer greenhouse gases, the company said, and it uses 75% less water and requires about 95% less land than conventional ground beef.

“The Impossible Whopper is all Whopper, no beef,” Burger King said. “It’s as juicy, craveable and delicious as the original Whopper.”

The debut of the heme-based handheld at Burger King follows Red Robin Gourmet Burgers and Brews’ announcement in late March that the chain would offer the Impossible Burger at its restaurants. In January, White Castle restaurants began rolling out the Impossible Slider to its 377 locations. Other restaurants serving the meat-free burger include Wahlburgers, Umami Burger and Fatburger.