Heat two teaspoons oil in a non-stick pan. Add bean sprouts and sauté for five-six minutes or till cooked. Transfer into a plate and set aside.
Heat the remaining oil in the pan. Add garlic and sauté for a minute. Add onion and sauté till it becomes translucent. Add mushrooms and carrots and sauté for a minute. Add chicken cubes and sauté for two minutes. Add MSG, salt, sugar, chicken stock and bring it to a boil. Cover and cook till the liquid is almost evaporated and chicken is nearly done. Add the sautéed bean sprouts and mix well. Add crushed peppercorns and soy sauce and mix well and cook till the chicken is done.
Serve the chicken hot garnished with chopped parsley.