Cut the gai lan in half crossways – this is so you can start to cook the stems first as they take the longest. Cut any really thick stems in halves lengthways.
Heat the peanut oil in a small to medium sized frying pan over medium heat. Add the sliced garlic. Cook, turning the garlic, for 2 minutes or so until the garlic is golden brown. Now watch this as it can go from raw to burnt quite quickly. Remove the garlic to paper towel and set aside. Keep the oil and set that aside too.
Add an inch or two of water to a large, deep wok or frying pan. Add a little salt to the water and bring to a boil over medium-high heat. Add the gai lan stems. Cover and cook for 1 to 2 minutes depending on their thickness.
Add the leafy tops and stir to combine. Cook, covered 1 to 2 minutes, until leaves are tender and just wilted and the stalks are tender-crisp. Drain well and transfer to a serving platter.
Combine remaining ingredients in a small bowl. Drizzle the warm peanut oil over the gai lan. Then the oyster sauce mixture. Sprinkle with crispy garlic. Serve immediately. Serves 4 to 6.
