Mongolian beef is a dish from Taiwan[1] consisting of sliced beef, typically flank steak, usually made with onions.
[2] The beef is commonly paired with scallions or mixed vegetables and is often not spicy.
The dish is often served over steamed rice, or in the US, over crispy fried cellophane noodles.
It is a staple dish of American Chinese restaurants.
Mongolian beef is among the meat dishes developed in Taiwan where Mongolian barbecue restaurants first appeared.