Cut all the vegetables and other ingredients into bite-sized pieces.

Stir-fry the pork first, then add the vegetables in order of how long they take to cook. Season with salt and pepper.

Add the reserved shiitake soaking liquid and enough water to make the soup base, then pour it all in at once. Simmer until the sauce thickens, then add the oyster sauce and adjust the flavor to taste.

Pour the sauce generously over the sara udon noodles. Add mustard or vinegar if you like.

You can also pour the sauce over crispy pan-fried yakisoba noodles. For Chinese rice bowls, I add oyster sauce to store-bought chop suey mix for extra flavor.