Cut the chicken breast into strips across the breast 2-3mm (⅛") thick and place it in a bowl.
Mix together the soy sauce, oyster sauce, Chinkiang vinegar, sugar and MSG, then pour it over the chicken and allow it to sit whilst you prepare the vegetables.
Peel the red onion and cut it in half, then cut it into slices 2-3mm (⅛") thick.
Cut the mushrooms into slices 2-3mm (⅛") thick.
Cut the sugar snap peas at a 45 degree angle into strips 2-3mm (⅛") thick.
Peel the garlic cloves and slice them as finely as you can.
Cut the spring onion at a 45 degree angle into rounds 2-3mm (⅛") thick separating the green parts from the white parts.
Just before you start cooking remove the chicken from the sauce, keeping the two separate.
Heat a frying pan or wok over a fiercely high heat, and when it is shimmering, add one (1) tablespoon of cooking oil. Throw in the chicken, red onions and mushrooms, and stir fry for 2 minutes.
Add the garlic and white parts of the spring onion and stir fry for 30 seconds.
Add the sugar snap peas and bean sprouts stir fry for 30 seconds, then add the sauce and cook for 30 final seconds. Remove the pan/wok from the heat and transfer the stir-fried ingredients to a bowl, and clean the pan or wok.
Crack the eggs into a large bowl and lightly beat with a whisk, then add the stir fried ingredients and mix them together.
Heat the wok again over a fierce heat, and when it is hot, add the remaining tablespoon of cooking oil.Add the egg foo young mix to the wok and then allow the eggs to set on the wall of the wok. Then fold, allowing more egg to set on the side of the wok. Repeat this process until all of the eggs have just cooked.