Stir-fried King Oyster Mushrooms with Gai Lan in Ginger Scallion Sauce

Prepare Vegetables: Trim and peel gai lan stems if tough, then cut into 2-inch pieces. Slice king oyster mushrooms diagonally into 1/4-inch thick pieces. Thinly slice half of the ginger and mince the other half. Chop green onions, separating white and green parts. Mince garlic.