Equipment
Ingredients
Beef and Marinade
- 450 g flank steak, trimmed of excess fat
- 15 ml light soy sauce
- 15 ml shaoxing wine
- 10 g cornstarch
- 2 g baking soda
- 15 ml water
- 15 ml neutral oil
Aromatics and Vegetables
- 300 g sweet onion, cut into 2cm wedges
- 15 g fermented black beans, rinsed and roughly chopped
- 15 g garlic, minced
- 10 g fresh ginger, minced
- 30 ml neutral oil
Stir-Fry Sauce
- 60 ml chicken stock
- 20 ml oyster sauce
- 15 ml light soy sauce
- 5 ml dark soy sauce
- 5 g granulated sugar
- 5 ml sesame oil, toasted
- 5 g cornstarch
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 370 kcal
- Protein
- 27 g
- Carbohydrates
- 17 g
- Fat
- 20 g
- Fiber
- 2 g
- Sugar
- 6 g
- Sodium
- 994 mg
- Saturated Fat
- 5 g
- Monounsaturated Fat
- 3 g
- Polyunsaturated Fat
- 1 g
- Cholesterol
- 78 mg
- Potassium
- 596 mg
- Calcium
- 69 mg
- Iron
- 2.5 mg
- Magnesium
- 36 mg
- Phosphorus
- 278 mg
- Zinc
- 4.8 mg
- Vitamin A
- 0 mcg
- Vitamin C
- 7 mg
- Vitamin D
- 0.1 mcg
- Vitamin E
- 0.4 mg
- Vitamin K
- 2 mcg
- Vitamin B6
- 0.8 mg
- Vitamin B12
- 1.4 mcg
- Thiamin
- 0.11 mg
- Riboflavin
- 0.16 mg
- Niacin
- 8.5 mg
- Folate
- 30 mcg
- Water
- 156 g
Sources: Aggregated Public Data, USDA FoodData Central
Method
Slice the flank steak against the grain into 5 millimeter thick slices to ensure tenderness. Wash hands and sanitize the cutting board thoroughly after handling raw meat to prevent cross-contamination.
Place the sliced beef into a mixing bowl. Add the light soy sauce, Shaoxing wine, cornstarch, baking soda, and water. Vigorously massage the liquids into the meat until fully absorbed, then fold in the neutral oil to seal it. Let sit at room temperature for 20 minutes.
In a small mixing bowl, whisk together the chicken stock, oyster sauce, light soy sauce, dark soy sauce, granulated sugar, toasted sesame oil, and cornstarch until the sugar and cornstarch are completely dissolved.
Heat a wok or large heavy-bottomed skillet over high heat until lightly smoking. Add 15ml of neutral oil. Spread the marinated beef in a single layer and sear without moving for 1 minute to develop a crust. Stir-fry for another minute until lightly browned outside but still slightly pink inside, reaching at least 63 degrees Celsius or 145 degrees Fahrenheit internally. Remove the beef and set aside.
Wipe the wok clean if necessary, return it to medium-high heat, and add the remaining 15ml of neutral oil. Add the sweet onion wedges and saute for 2 minutes until they begin to soften and pick up a slight char on the edges.
Push the onions to the sides of the wok to create a space in the center. Add the chopped fermented black beans, minced garlic, and minced ginger to the clearing. Saute briefly until highly aromatic, about 30 seconds, before tossing together with the onions.
Return the seared beef and any accumulated resting juices to the wok. Give the prepared stir-fry sauce a quick stir to re-incorporate the cornstarch, then pour it over the meat and vegetables. Simmer everything together, tossing continuously, for 1 to 2 minutes until the sauce thickens to a glossy coating.
Remove the wok from the heat immediately to prevent overcooking the beef. Serve hot alongside steamed rice.
Chef's Notes
- Velveting technique: The combination of cornstarch, baking soda, and water in the marinade protects the beef fibers from seizing up under high heat, yielding the signature tender texture found in Chinese restaurant stir-fries.
- Wok hei: Cooking in smaller batches helps maintain the high heat required to achieve wok hei, the smoky flavor characteristic of proper stir-frying. If using a standard home stove, do not overcrowd the pan.
- Preparation is key: Stir-frying happens extremely fast. Measure all ingredients and mix your sauce entirely before you turn on the stove.
Storage
Refrigerator: 3 days — Store in an airtight container. The sauce may thicken significantly when cold.
Freezer: 1 month — Freeze in airtight containers or heavy-duty freezer bags. Texture of onions may soften upon thawing.
Reheating: Reheat gently in a skillet over medium heat with a splash of water until steaming hot.
Troubleshooting
The beef is tough and chewy.
Cause: The beef was sliced with the grain instead of against it, or the wok was not hot enough causing the meat to steam rather than sear.
Fix: Cannot be fixed once cooked. Next time, allow the wok to preheat fully.
Prevention: Examine the direction of the muscle fibers on the flank steak and cut perpendicularly across them. Ensure the wok is smoking hot before adding the meat.
The sauce is too salty.
Cause: The fermented black beans were not rinsed, or a heavy-handed pour of soy sauce was used.
Fix: Stir in a small splash of water and an extra pinch of sugar to balance the salinity.
Prevention: Always rinse fermented black beans briefly under cold water before chopping to remove excess surface salt.
The sauce is thin and watery.
Cause: The cornstarch settled at the bottom of the bowl and was not mixed in, or the sauce did not reach a boil.
Fix: Push ingredients to the side, whisk 2g of cornstarch with 5ml of cold water, stir it into the simmering sauce, and boil for 30 seconds.
Prevention: Always re-whisk the sauce slurry immediately before pouring it into the hot wok.
Cultural Context
Douchi, or fermented black beans, are the oldest known food made from soybeans, dating back over two millennia in China. They deliver an intense, savory, slightly bitter umami punch that forms the backbone of iconic regional dishes like mapo tofu and twice-cooked pork.
