You will find many versions of this Chinese sauce, with or without one or the other ingredient, but there will always be oyster and soy sauce. This is my summer version, with colourful peppers, but I do exactly the same sauce and noodles with broccoli and mushrooms in the winter.
For the sauce whisk in a bowl:
Soy, 2 volumes
Oyster, 2 volumes
Mirin, 2 volumes - or Sugar 1 volume
Fish Sauce, 1 volume
Add and stir will to break up any lumps:
Cornflour, 1/3 volume
Sesame Oil, 1/3 volume
In a pot of boiling water cook the:
per instruction, usually 6 minutes is enough. Drain and keep in cold water until use. They will keep well in the fridge for a few days.
In a big pan (that will later also fit the noodles and sauce) over medium heat, in a mixture of sesame and olive oil, lightly saute:
Garlic, finely chopped
Ginger, finely chopped
Chilli, finely chopped - optional, if you want some heat
Peppers, in thin strips - green, red, yellow, orange, whatever is available
and allow them to sweat and soften for a few minutes. Return noodles to the pan and mix with the peppers. Add the sauce and let it bubble away and coat the noodles and vegetables. Taste to check the saltiness and adjust seasoning.
Coriander, fresh leaves, chopped - or green parts of spring onions
Note on quantities: The volume measurement for the sauce is 1 tbsp which I doubled for 4 blocks of egg noodles.