In a small bowl, whisk together the cornflour and dark soy sauce until smooth. Then, add the light soy sauce, Chinese cooking wine, white sugar, sesame oil, and white pepper. Combine thoroughly until all ingredients are well-blended. Set aside for later use.

Slice your chosen protein into bite-sized pieces. Toss the sliced protein with about 2 teaspoons of the prepared sauce and let it marinate for a few minutes while you heat up the wok.

Heat vegetable oil in the wok until shimmering, add the finely sliced onion and minced garlic. Stir-fry for about 30 seconds until fragrant.

Add the marinated protein to the hot wok, spreading it out into a single layer. Sauté for approximately 1 minute, stirring occasionally until white on the outside.

Toss in the carrot batons and sliced red capsicum. Stir-fry for about 2 minutes until crisp-tender.

Add the Lo Mein noodles, prepared sauce, and 1/4 cup of water to the wok. Toss for about 30 seconds.

Add the chopped green onions to the wok. Toss everything for another minute, allowing the green onions to wilt slightly.

Turn off the heat and transfer the cooked Lo Mein Noodles to serving plates. Garnish with extra green onions if desired.