This is likely the most secretive burger in food history.

When a reporter with The Guardian got to try it in 2012, he wasn't allowed to write what he tried, who made it, nor what it tasted like.

It's a rather ordinary-looking juicy, bloody burger. But this hunk of "beef" actually contains no meat.

The company behind it, Impossible Foods, appeared on the food scene in 2015 when Google reportedly made a bid to buy the startup. It's believed the tech giant offered between $200 million and $300 million, but the two companies couldn't agree on a selling price.

The people who have tried the burger write glowing reviews of its beef-like texture, tender center, and mouthwatering smell.

After years of relative silence, the company is peeling back the curtain on what makes its burger so unmistakably meaty.

The secret ingredient packed in every Impossible Foods veggie burger is, essentially, plant blood.

A molecule called heme that's found in plants and animals carries oxygen through the bloodstream (and in plants, through the mechanisms that produce energy). Heme makes your blood red, turns meat pink, and gives the traditional burger its slightly metallic flavor and delicious aroma when it's exposed to sugars and amino acids.

Mmmmm, meat. Chris Snyder

Impossible Foods injects the magic molecule into yeast, which becomes a temporary heme factory. This process is more cost-effective and sustainable than extracting heme from plants like soybeans, NPR reports, and allows the company to produce it in massive quantities.

"No other plant-based meat has this ingredient," a spokesperson for Impossible Foods tells Tech Insider in an email.

The result? A burger that satisfies even the most ardent meat-lovers. The spokesperson tells us several thousand people have tasted the burger and few can tell the difference between the Impossible Foods burger and one made from a cow.

The burger will be served in high-end restaurants starting in New York this summer. This will allow the company to gather valuable product feedback from chefs and consumers before a retail launch, which could be years away.

"The cow is not going to get any better at making a burger, but we will," the spokesperson says.