Asian greens prepared with oyster sauce and garlic oil is a popular dish in Chinese cuisine. Asian greens such as bok choy (known as “xiǎo báicài” 小白菜 in Mandarin), choy sum (“cài xīn” 菜心 in Mandarin) and Chinese broccoli (“jiè lán” 芥兰 in Mandarin and “gai lan” 芥蘭 in Cantonese) can be used.
Chinese woks (known as “chao guo” 炒锅) are traditionally made from cast iron and these woks, coupled with a very strong, high flame tend to give the best results. Cast iron woks retain heat better than other materials and the temperature does not fluctuate much compared to woks of other materials. Consequently, once the greens are thrown into the boiling water, some woks may see a sudden drop in heat levels which generally does not happen when cooking with cast iron woks. This sudden drop in heat level means the greens take a longer time to cook which does not produce the best color, aroma, texture and taste compared to greens that are cooked quickly at a high temperature.
This advantage of providing a uniform and stable heating level is a key reason cast iron woks produce superior results when cooking Chinese food.
Additionally, well-seasoned woks impart a distinct “wok flavor” to the food known as “wok hay” 鑊氣 in Cantonese (usually spelled “wok hei” but the pronunciation is closer to “wok hay”) which literally means “wok energy” (wok qi). However an intense flame is necessary to achieve this effect and thus may be extremely difficult to achieve with home stove top flames.
A well-seasoned cast-iron wok is highly durable and could last for generations and there are families today that cook with cast-iron woks passed down from the grandmothers or great-grandmothers of the family. For instance, the cast-iron wok used by my maternal grandmother (who was born in 1928) is still treasured and frequently used by her children.
When blanching the greens, an overcrowded wok must be avoided; if the wok is overcrowded, the leaves don’t cook quickly and end up “sweating” and slow cooking instead, resulting in greens that are limp, discolored and bland.
Chinese food tastes best when consumed hot and freshly cooked, so serve straight away.
- 1/2 lb Asian greens such as bok choy or choy sum or Chinese broccoli
- 1/2 teaspoon oil
- 1-2 tablespoons oyster sauce
- 2 teaspoons light soy sauce
- 2 tablespoons boiling hot water
- Freshly ground white pepper as desired (optional)
For garlic oil:
2 tablespoons oil
4-5 cloves of garlic – very finely minced
In a small glass / ceramic bowl, combine oyster sauce and light soy sauce. Mix well and set aside.
Prepare the garlic oil. Heat up a wok over high flame. Do not add oil until the wok is well heated up.
Pour 2 tablespoons oil and let the oil heat up.
Swirl the wok to evenly coat the oil around the wok.
Add minced garlic, fry till garlic turns brown and fragrant. Stir frequently. Do not burn the garlic.
Pour this garlic oil into the bowl of oyster sauce and light soy sauce. Stir and set aside.
Wash greens thoroughly to remove dirt and grit. Optionally, cut into halves or quarters lengthwise.
Have a bowl of cold water ready. Set aside.
In a cast iron wok, bring some water to a rolling boil over high heat.
Add salt and 1/2 teaspoon oil.
Then add the washed and drained greens.
Toss quickly then cover with a lid, until greens are cooked through yet retains its vibrant green hue, fresh taste, crunch and texture. This usually takes just a few minutes, depending on the strength of the flame and the type of wok (cast iron woks retain heat better than other metals and hence generally require less time).
Once cooked, immediately take out the greens and soak them in the bowl of cold water set aside earlier.
Once cooled, arrange the greens neatly on a plate.
Pour two tablespoons of hot water (some take two tablespoons from the boiling water used to blanch the greens) into the bowl of oyster sauce mixture prepared earlier. Mix well.
Drizzle the sauce over the freshly cooked greens.
Serve straight away with rice.