The new menu item may seem like a great option for vegetarians to enjoy a meatless burger, but that might not completely be the case.

While the patty is made entirely of plant products, it’s grilled on the same broiler that gives the fast-food chain’s food its signature flavor, the company acknowledged.

Vegans were already upset, says TODAY, as the burger came topped with mayo, but now many vegetarians are calling the fast-food chain out on Twitter for the cooking method.

The Impossible Whopper goes nationwide on Thursday.