Whole mushrooms are braised in a rich, glossy abalone-flavored sauce until deeply savory. This vegetarian-adaptable family dish delivers restaurant-quality umami in a simple preparation.
Wipe and trim the whole mushrooms; gently score tops of shiitake mushrooms for appearance. Rinse baby bok choy and cut scallions into 2-inch sections.
Heat 2 tbsp vegetable oil in a large skillet or wok over medium-high. Add mushrooms in a single layer and sauté for 3-4 minutes, stirring occasionally, until lightly browned.
Add the abalone sauce, soy sauce, oyster sauce, sugar, and water to the pan. Stir gently and bring to a simmer over medium heat.
Cover and lower heat to maintain a gentle simmer. Add bok choy and scallions around the mushrooms. Braise, covered, for 10 minutes until mushrooms are tender and bok choy is bright.
Mix cornstarch with 2 tbsp water in a small bowl. With the pan uncovered and heat at medium, stir in cornstarch slurry and cook for 1-2 minutes until the sauce is glossy and thickened. Finish with sesame oil and a sprinkle of white pepper before serving.