Bring a large pot of salted water to a rolling boil. Add the egg-free wheat noodles and cook according to package instructions until just al dente (usually 3–5 minutes). Stir occasionally to prevent sticking. Drain immediately and rinse under cold running water to stop cooking. Toss with 1 teaspoon vegetable oil to prevent sticking and set aside.

Prepare Sauce

In a small bowl, combine light soy sauce (3 tbs), dark soy sauce (1 tsp), oyster or vegetarian mushroom sauce (1 tbs), vinegar (1 tsp), sesame oil (1 tsp), cornstarch (1 tsp) and 2 tablespoons water. Whisk until the cornstarch dissolves and set aside.

Vegetables & Aromatics

Prep aromatics: peel and finely mince 4 garlic cloves and grate or finely mince 1 tablespoon ginger. Slice the onion thinly. Trim and slice the green onion stalks, keeping whites and greens separate.

Heat a large wok or wide skillet over high heat until very hot. Add 2 tablespoons vegetable oil and swirl to coat. Add the white parts of the green onions, minced garlic and ginger. Stir-fry for 15–20 seconds until fragrant but not browned.

Add sliced onion, julienned carrot, sliced bell pepper and shredded cabbage. Spread the vegetables out and let them sit for 20–30 seconds to get a little char, then stir-fry for 1–2 minutes until they begin to soften but remain crisp-tender. If using beansprouts or snow peas, add them in the last 30–45 seconds so they stay crunchy.

Combine & Finish

Increase heat to very high. Add the cooked, drained noodles to the wok with the vegetables. Toss to combine and break up any clumps.

Give the prepared sauce a quick stir (cornstarch may settle) and pour it evenly over the noodles and vegetables. Toss continuously for 1–2 minutes so the sauce thickens and coats everything. If the mixture seems dry, add 1–2 tablespoons of water and toss again.

Season with salt (1/2 tsp), black pepper (1/4 tsp) and chili sauce (1 tsp) or red chili flakes to preferred heat. Taste and adjust soy or salt as needed.

Turn off the heat. Add the green parts of the spring onions, drizzle 1 tsp extra sesame oil if desired, and toss briefly. Squeeze half a lime or lemon over the noodles if using.

Transfer to a serving platter and garnish with chopped fresh coriander (or extra spring onions). Serve immediately.