Carnivorous burger lovers looking to go vegetarian or vegan are currently living in the golden age of guilt-free, plant-based meat. As the Beyond Burger and its sausage counterpart hits more and more grocery stores across the country, and upscale chains and standalone burger joints adopt Impossible Foods’ plant-based patties that look and taste close to ground beef, the options and availability of these meat-free offerings are ever increasing. But let’s face it, when it comes to hamburger market saturation, the big players aren’t the restaurants with cloth napkins or brioche buns. They’re the ones with the drive-thru windows. That’s why it’s rather noteworthy when, today, White Castle announced that it will be the first fast food chain to adopt the vegan Impossible Slider nationwide.

White Castle first put the Impossible Burger on the menu in April, with a rollout in New York City, New Jersey, and Chicago areas. At the time it was the first national fast food chain to do so, and the company made it clear the limited rollout was a prelude to a wider release. At the time, we tried the Impossible Slider and found it to be a near flawless substitute to White Castle’s signature smallscale burger staple.

The burger comes with a square Impossible patty, topped with smoked cheddar cheese, pickles, and onions (meaning you’ll need to order it without the cheese if you’re looking for a truly vegan option). The “meat” is made with water, wheat protein, potato protein, coconut oil, and soy leghemoglobin, which contains a protein called "heme" that, when cooked, breaks down like meat and releases the burger's "bloodlike" juices. According to Impossible Foods, the plant-based burger’s production “requires less than a quarter of the water, less than 5% of the land and generates less than an eighth of the greenhouse gas emissions required to produce the same quantity of ground beef from cows.”