Pad Thai is a popular Thai noodle dish that is typically made with thin, flat rice noodles. The noodles are stir-fried with a sweet-savory-sour sauce that usually includes ingredients such as tamarind paste, fish sauce, vinegar, and sugar. Other common ingredients in Pad Thai include bean sprouts, garlic chives, scrambled egg, firm tofu, and a protein such as chicken, shrimp, pork, or beef. Some recipes also call for shredded carrots, green onions, and peanuts as toppings. Vegetarian or vegan versions of Pad Thai can be made by leaving out the egg and substituting the fish sauce for more soy sauce.