
This saucy beef chow fun pairs tender marinated flank steak with wide fresh rice noodles, mushrooms, napa cabbage, and crisp bean sprouts. A glossy soy-oyster gravy coats every noodle for a Cantonese-style stir-fry that tastes rich, savory, and deeply satisfying.
Bring the fresh rice noodles to room temperature, then separate or cut them into wide strips about 1 1/2 inches across. Handle them gently so they do not crack.
Marinate the beef: in a shallow bowl, combine the sliced flank steak with baking soda, soy sauce, 1 tbsp water, 1 tsp vegetable oil, and 1/2 tsp cornstarch. Mix until the liquid is absorbed and the beef is evenly coated, then let it stand at room temperature for 30 minutes.
Make the sauce by stirring together the warm stock, light soy sauce, dark soy sauce, oyster sauce, sugar, sesame oil, and white pepper. Keep it near the stove. In a separate small bowl, mix the remaining cornstarch with 2 tbsp water to make a slurry.
Heat a wok over high heat until very hot. Add 2 tbsp canola oil, then sear the beef in a single layer for about 30 seconds per side, just until mostly cooked. Transfer the beef back to its bowl.
Lower the heat to medium and add the remaining 1 tbsp canola oil. Add the ginger and stir for about 20 seconds, then add the garlic, shiitake mushrooms, and the white parts of the scallions.
Turn the heat back to high and stir-fry for 15 seconds. Add the Shaoxing wine, followed by the napa cabbage, and toss briefly until the cabbage begins to soften.
Pour in the prepared sauce. When it starts to simmer, add the fresh rice noodles and fold them through the sauce with a wide spatula, using gentle lifting motions to avoid breaking them.
Once the noodles are hot, about 30 seconds, add the bean sprouts and seared beef. Fold everything together until the beef is warmed through and the sprouts are lightly softened but still crisp.
Add the green scallion tops. Stir the cornstarch slurry again, then drizzle in about half while gently tossing. Cook for 20 seconds, then add more slurry as needed until the sauce lightly coats the noodles and the back of a spoon.
Let the sauce bubble for at least 20 seconds after the last addition of slurry so the starch fully cooks. Serve immediately, with chili oil on the side if desired.
Use fresh wide rice noodles if possible; dried noodles can work, but they should be soaked or cooked just until pliable before stir-frying. Keep the wok hot and avoid over-stirring once the noodles are added, since fresh rice noodles break easily. If the sauce gets too thick, loosen it with a splash of warm stock; if it is too thin, add a little more slurry and simmer briefly.