Slice King Oyster Mushrooms into thick slices, about the size of scallops.
Place slices between two chopsticks and slice horizontally and vertically, creating a grid of slices. Use the chopsticks to make sure you don’t slice all the way through the mushrooms.
Boil the mushrooms for 3 minutes to ensure they don’t absorb too much oil.
Dry mushrooms with a paper towel after boiling.
Heat sesame oil in a pan. Add garlic to pan and cook for 1-2 minutes.
Add mushrooms to the pan. Cook mushrooms for 3 minutes on each side, for a total of 6 minutes. Optional: remove excess oil from the pan after 6 minutes.
While mushrooms are cooking, combine cornstarch, soy sauces, sugar, and water in a separate container.
Add sauce to pan with mushrooms and thicken for 1 minute.
Add green onions to the pan.