Heat the peanut oil in a large nonstick frying pan over moderately low heat.
Add the garlic and ginger and cook for 1 minute or until slightly softened.
Add the stock and 1/4 cup water, cover and cook for 7 minutes or until the garlic and ginger are very soft.
Add the capsicum and carrots and cook for 1 minute. Add the bok choy and toss until well coated.
Sprinkle with the sugar and a pinch of salt and cook for 4 minutes (6 minutes if using green cabbage) or until tender.
Drizzle with the sesame oil and serve hot.