Trim bok choy, cut into halves or quarters, and soak in water for 10 minutes to remove dirt.

Rinse bok choy under running water and drain well.

Slice king oyster mushrooms into thick pieces and score both sides with a crisscross pattern.

Slice green onions thinly and set aside.

Boil water with 1/2 tbsp salt and 1 tbsp vegetable oil, then blanch bok choy for 50 seconds.

Drain bok choy and rinse under cold water, then squeeze out excess water.

Heat a pan with vegetable oil, season mushrooms with salt and pepper, and grill until golden brown on both sides.

Mix 1 tbsp cornstarch with 3 tbsp water to create a slurry.

In a pan, combine 1/2 cup water, 1.5 tbsp oyster sauce, 1.5 tbsp soy sauce, 1 tbsp sugar, and 2 tbsp cornstarch slurry. Cook until thickened.

Add green onions to the sauce and mix well.