Vegetarian Mongolian Beef is a meat-free version of the dish that is just as delicious and satisfying. Instead of beef, this recipe often uses tofu or seitan as a protein substitute. The tofu or seitan is marinated and cooked in a similar way to the traditional recipe, allowing it to absorb the flavors of the sauce. The result is a vegetarian dish that is full of flavor and texture, making it a great option for those who follow a plant-based diet or simply want to try something different.