In fast food, making something success once is, at best, a lucky break and, at worst, a fluke. But the true mark of success is doing something again and again. So has Burger King's Impossible Whopper—a version of the brand's signature sandwich made with a plant-based patty from Impossible Foods—been a success? Here's an affirmative sign: The King has announced that it will be testing three more plant-based Impossible burgers starting this week.

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Similar to the Impossible Whopper, the new Impossible Whopper Jr., Impossible Burger, and Impossible Cheeseburger will take existing sandwiches and give them the plant-based treatment by swapping their patties for a meat-free version from Impossible Foods. Beyond simply being new menu items, these three burgers arrive with additional intrigue. First, both the Impossible Burger and the Impossible Cheeseburger will be offered as part of the brand's King Jr. kids' meals—which Burger King says makes them the first national fast food chain in the U.S. to launch a plant-based menu entrée on the kids' menu. Second, as Business Insider points out, these new, smaller burgers will also offer Impossible burgers at a more affordable price point.

For now, these new Impossible burgers will only be sold at 180 Burger King locations across Milwaukee, Wisconsin; Cedar Rapids, Iowa; Augusta, Georgia; Cincinnati, Ohio; and Buffalo, New York. But if Burger King sees similar results as they have with the Impossible Whopper, don't be surprised if these items eventually get a nationwide rollout. As the chain writes, "The Impossible Whopper has quickly become one of the most successful product launches in brand history leading to outstanding comparable sales performance of positive 5 percent this past quarter."

Meanwhile, it's not only America that's seeing new plant-based options. In the same announcement, Burger King also broke the news of their new Rebel Whopper—a meat-free Whopper launching in 2,400 European locations. Interestingly, however, this Euro plant-based Whopper doesn't use an Impossible patty; instead, BK partnered with the brand The Vegetarian Butcher across the Atlantic. Late last year, The Vegetarian Butcher was acquired by the food giant Unilever which owns a laundry list of brands from Ben & Jerry's to Axe.