In a bowl, mix the sauce ingredients and set aside.
Cook the noodles according to the packet instructions, 2 minutes less than stated, then drain and set aside.
Place a large high-rimmed pan or wok over high heat. Spray with avocado oil and add the beef and ground white pepper. Mix and cook for 6–8 minutes, or until no longer pink and the moisture has evaporated.
Add the spring onion and half of the sauce and cook for 2 minutes, or until reduced and the beef starts to crisp. Remove from the pan and set aside.
In the same pan or wok over medium-high heat, add more spray oil, the onion, and the bell pepper (capsicum). Mix and cook for 5–6 minutes, or until softened and the onion is slightly translucent. Add the garlic and ginger and cook for 1½ minutes, mixing regularly.
Add the crispy beef, drained noodles, and remaining sauce, and cook for 2 minutes until everything is well coated in the sauce. Remove from the stovetop.
Serve in 5 x 750ml meal prep containers and garnish with spring onion, sesame seeds, and sliced chilli (optional). Dig in.