The Impossible Burger Is Coming to Burger King

White Castle was just the start: Impossible Foods is now partnering with Burger King, launching the Impossible Whopper for a test starting today at 59 Burger King outlets in St. Louis, Missouri. It's an entirely different burger to the sliders served at White Castle, and that means there's more Impossible Burger non-meat involved.

It's equal parts silly April Fools' teaser and actual product launch at the U.S.'s second-largest burger chain. For now, the company is staying quiet on whether there'll be a nationwide roll-out. The Whopper launch comes after another regional debut: a Philly Cheesesteak that's currently exclusive to, well, Philadelphia of course.

If it's been a while since you've had a Whopper, or you've been vegetarian for a while, the Impossible Whopper includes a flame-grilled, (improved) plant-based burger patty, with lettuce, tomato, pickle and onion toppings. Oh, and don't forget the mayo and ketchup.