The black pepper Angus steak at Panda Express features a tasty sauce whose consistency resembles A1 steak sauce. However, its ingredients have never been made public.

Based on taste tests and flavor profiles, some believe the sauce features soy sauce, oyster sauce, beef stock, and a thickener of either cornstarch or tapioca starch.

Some copycat recipes add in ingredients like brown sugar, Chinese cooking wine, and seasonings like chili and ginger. The odds of the sauce being soy sauce-based are high.