Hit up some oil in wok, add green onion white to fry over slowest fire until slightly browned and seared. Add ginger shreds in.
Then place mushrooms in, add oyster sauce and soy sauce. At the very beginning, there will be lots of water. Continue to evaporate most of the water. Takes 2 to 3 minutes. Mix in sesame oil.
Transfer out and sprinkle fresh ground pepper.
Video
Notes
If you want to turn this into vegan friendly, use 1 tablespoon of light soy sauce with 1 teaspoon of cornstarch to replace oyster sauce.