In a large bowl wash the beef cube in cold running water for five minutes. Drain for 30 minutes. In a mixing bowl baking soda, cornstarch, salt, sugar, Chinese rice wine, oil and water. Mix together into beef a blend well. Marinade the mixture overnight.
In a hot skillet coat with oil and brown beef cube in small amount. Brown all side. Place onto a warm serving plate.
In the same skillet reheat and coat with oil. Add Mushrooms, garlic and scallion and stirfry for two minutes. Add in beef stock and oyster sauces bring to a boil. Thicken with cornstarch roux. Blend in the steak kew mix well; pour into a warm serving platter.