A bone-dry sherry goes well with the oyster and soy sauces in this dish.
Soak dried shiitakes in hot water in a large bowl for approx. 20 min. until the caps are tender. Save the water. Mince garlic and ginger. Remove stems from shiitake and cut a cross into the top.
Wash bok choy and cut a cross near the roots.
Bring a large saucepan of water with oil and salt to a boil. Dip the roots of the bok choy into the water for approx. 20 sec., then immerse all of it for approx. 1 min. Transfer to an ice bath to stop cooking process.
In a small bowl, mix together oyster sauce, dark soy sauce, corn starch, and reserved mushroom water to form a thick sauce. Heat up oil in a large frying pan and sauté ginger and garlic over medium heat for approx. 1 min. Add shiitakes, sugar, and salt and stir fry for approx. 1 min. Deglaze with sauce, stir thoroughly, and remove from heat.
Arrange bok choy in a bowl for serving. Place the shiitake mushrooms in the center. Garnish with sauce. Enjoy!