Add chicken, egg, red chilli flakes and cornstarch to a large bowl and mix well.
To make the stir fry sauce, add soy sauce, white vinegar, Sriracha, ketchup, sugar, white pepper and red chilli flakes to a bowl and mix well.
Heat fresh noodles in a pot of boiling water as per the packet instructions. Drain and set aside.
Heat one tablespoon oil in a large wok on high. When smoking, add marinated chicken. Stir-fry for 4-5 minutes, tossing constantly until chicken is seared and almost cooked through the middle. Remove and set aside.
Add the remaining oil to the wok. Add onion and stir-fry for a minute until onion is glazed. Add cabbage, spring onion, garlic and ginger. Cook for 1-2 minutes until fragrant. Add cooked noodles, chicken and MSG if using. Add the stir fry sauce. Stir-fry for 2-3 minutes, tossing constantly until mixed well and heated through. Test to check if chicken is thoroughly cooked.
Remove from heat, add coriander and mix well. Serve immediately.
Notes
Chicken - Boneless, skinless chicken thigh works best in these Chicken Schezwan Noodles. You can use chicken breast fillets or tenderloins as a substitute.
Noodles - Fresh chow mein noodles are perfect for this dish. Chow mein noodles are thinner than udon noodles and have a similar thickness to ramen or egg noodles. If using uncooked noodles, try plain Chinese instant noodles or thin egg noodles, which are available in Asian sections of supermarkets. Two 100g cakes would be the right amount for this recipe.
Soy sauce - Use light soy sauce for this dish.
Vinegar - White vinegar for the acidic tang. Indo-Chinese dishes often use white vinegar to add acidity. Do not substitute with rice wine vinegar as it changes the flavour profile.
Herbs - Fresh coriander is a key ingredient of Indo-Chinese cuisine. Don't skip this herb for that true, authentic Indo-Chinese taste.
Storage Suggestion - This will keep fresh in the fridge in an air-tight container for up to three days. It can be frozen for up to one month.