The Impossible Burger hasn't been easy to find.

Imitation meat made by Impossible Foods Inc. has become an unexpected craze, reaching more than 10,000 restaurant menus over the summer, by the company’s count. In a sign of both popularity and supply-chain problems, the Impossible Burger is sometimes impossible to obtain at these restaurants due to a months-long shortage.

More than 30% of locations listed on Impossible’s website were not serving the product last month, according to a survey conducted by Bloomberg News. The data, drawn from a random sample of 902 locations across the U.S. and Asia, found particularly widespread outages in some regions. In Massachusetts and Maine, for example, as many as 65% of restaurants did not have the burger in stock during a 14-day period in July. About 10% of those restaurants told Bloomberg they had switched to a competing product made by Beyond Meat Inc.

Now, as Impossible moves onto menus at more than 7,000 Burger Kings in the U.S.—joining the roster of White Castles, Red Robins, Qdobas and thousands of indie restaurants offering its products—we want you to help us keep tabs on the spread of the plant-based burger. That’s why we’ve made Bloomberg’s Burger Stalker. Here’s how it works.

The map on this page includes all current restaurant locations in Impossible’s database, along with the most recent report of Impossible burger availability. A green dot on the map means the meatless burger is in stock, a red dot shows a reported outage. If you’re at a restaurant with Impossible on the menu, open up this page and tell us if the burger is available.

Why are we doing this? Silicon Valley-based Impossible Foods, like its principal rival Beyond Meat, has generated widespread consumer interest in convincingly meat-like alternatives to beef, designed to taste, feel and even “bleed” like actual red meat. Plant-based alternatives to established foods have already taken over more than 13% of the dairy market, according to a report from Barclays, and imitation beef could account for $140 billion in global sales within 10 years. A big shift to meatless alternatives could dramatically reduce the greenhouse-gas emissions tied to beef production.

But that all depends on startups like Impossible figuring out how to ramp up production. With your help, Bloomberg’s Burger Stalker can keep tabs on the rollout of Impossible Burgers—and we can help you figure out where to actually get your hands on the meatless meat.