In a recent interview with Forbes, Beyond Meat founder and CEO Ethan Brown revealed that the company’s popular vegan Beyond Burger outsold beef at a major southern California supermarket for the five-week period ending April 17th.

“So we’re selling more than Angus beef, more than 80/20 beef, more than grass-fed beef, by unit,” he told Forbes. “My expectation about being in the meat case was to simply hold on and not get thrown out. I never thought in a million years that we’d rise this quickly to be the number one seller in terms of patties in the meat case.”

When the Beyond Burger first launched in 2016, it was the first vegan meat to be sold alongside traditional meat counters. Its debut, at Whole Foods Market in Boulder, Colo., sold out in an under an hour. Chains like southern California’s Ralphs, a traditional supermarket, followed suit, making the vegan burgers visible to meat buyers by merchandising it alongside packaged meat.

“We made a rule that if [retailers] weren’t going to put it in the meat case, we weren’t going to sell it to them,” Ethan Brown said. “If they put it in the meat case, they can also put it wherever else they’d like but it definitely has to go in the meat case.”

The strategy worked.

Now in more than 25,000 stores across the U.S., including Walmart and Target, Beyond Meat has sold more than 11 million Beyond Burgers since debuting the patties in 2016. Sales for the company doubled last year, and are set to double again this year, Forbes reports. “Our biggest issue is keeping up with demand,” Brown says.

Demand is the biggest hurdle for the plant-based protein market in general, not just Beyond Meat; competitor burger brand Impossible Foods launched a new facility last year that, when running at full capacity, will be able to produce one million pounds of its Impossible Burgers a month. But that’s hardly a drop in the bucket for major burger sellers — McDonald’s, the world’s largest burger chain, serves nearly 70 million people every day, about 75 burgers every second.

But outselling beef at a major supermarket may help the company expand. Its already received two rounds of investments from leading meat producer Tyson Foods and has scored investments from Leonardo DiCaprio and Bill Gates.

Late last year Beyond Meat announced the launch of three Beyond Sausages. The brand took the same approach–not only is it now merchandising the sausages adjacent to meat cases, but it launched in traditional sausage bars including Schaller’s Stube in New York and Wurstküche in Los Angeles.