How to Make It
Trim the ends of the bok choy. Wash, pat dry with paper towels, and then set aside.
Heat a large skillet or wok over medium-high heat. Add the oil and then add the onion. Cook for 1-2 minutes or until soft, and then add the ground chicken. Stirring occasionally to break up and turn the chicken, cook for about 5 minutes or until the chicken is evenly browned and cooked through.
Stir in the soy sauce, sake (or vermouth), brown sugar, and rice vinegar and cook for 1 minute. Stir in the bok choy and cook for 1 minute, or until the bok choy is cooked and the sauce is heated through. Serve warm.