Marinate all of the chicken steak pieces using corn starch.
Take a frying pan and add one and a half cup of oil and then heat it. Add ginger and garlic in it and fry for approx. 2 minutes.
Now in the same oil add water along with brown sugar, soya sauce and vinegar. Cook all of them together on medium flame for 3 minutes and then remove the mixture from frying pan.
If the oil in pan is not enough, add some more oil in it and then cook chicken steaks on low flame from all sides until they become crispy.
Now pour the sauce prepared in step 3 on cooked chicken steaks.
Take chopped spring onions and fry them until they get brownish. Now sprinkle them on the chicken steaks.
Your Mongolian chicken is ready to serve. Serve with rice.