The vegan-friendly Impossible Whopper will soon be available at more than 7,000 Burger King locations nationwide. On April 1, Burger King added the Impossible Whopper to the menu of 59 St. Louis, MO locations to test the meat-free option with consumers. According to the fast-food chain, the plant-based burger will be introduced to additional test markets before expanding nationwide by the end of this year. The Impossible Whopper features a flame-grilled Impossible Burger 2.0 patty topped with sliced tomatoes, lettuce, mayonnaise, ketchup, pickles, and onions on a toasted sesame-seed bun—and can be made vegan if ordered without the mayonnaise. “The Impossible Whopper test in St. Louis went exceedingly well and as a result, there are plans to extend testing into additional markets in the very near future,” the company said in a statement. “Burger King restaurants in St. Louis are showing encouraging results and Impossible Whopper sales are complementing traditional Whopper purchases.”