Heat peanut oil in a wok or large skillet. When oil begins to smoke, quickly stir in 2 cloves minced garlic, ginger root, green onions and salt. Stir fry until onion becomes translucent, about 2 minutes.
Add chicken and stir until opaque, about 3 minutes. Add remaining 4 cloves minced garlic and stir. Add yellow onions, cabbage, bell pepper, peas and 1/2 cup of the broth and cover.
In a small bowl, mix the remaining 1/2 cup broth, soy sauce, sugar and cornstarch (or arrowroot flour). Add sauce mixture to wok/skillet and stir until chicken and vegetables are coated with the thickened sauce.
Serve immediately, over hot rice if desired.