In a medium bowl, combine 1/4 cup water, 2 tablespoons soy sauce, 1 tablespoon vegetarian oyster sauce, 1 teaspoon sugar, a pinch of ground black pepper, and 1 teaspoon sesame oil. Whisk until the sugar dissolves completely and set aside.

In a separate small bowl, mix 1 tablespoon cornstarch with 2 tablespoons water until smooth. Set aside.

Heat a large skillet over medium-high heat and add 1/4 cup of water. Once boiling, add cut baby bok choy, sprinkle with salt, and cover. Steam for 1 minute and transfer to a serving platter.

Wipe the skillet dry and return to high heat with 2 tablespoons peanut oil. Add the halved or quartered brown mushrooms in a single layer and sear for 1 minute until they begin to brown, then stir and cook for an additional 2 to 3 minutes.

Push the mushrooms to one side of the skillet, then add dried chili peppers, minced garlic, grated ginger, and chopped green onions. Stir for about 30 seconds until fragrant.

Return the steamed bok choy to the skillet, pour in the sauce, and toss gently to coat. Cook together for another 30 seconds.

Stir the slurry and add it to the skillet. Cook for an additional 2-3 minutes, stirring constantly until the sauce thickens. Serve hot.