Prepare the Sauce: In a small bowl, mix the water, soy sauce, vegetarian oyster sauce, sugar, black pepper, and sesame oil. Stir well until the sugar dissolves. Set aside.

Make the Slurry: In another small bowl, whisk together the cornstarch and water to form a slurry. This will help thicken the sauce later. Set aside.

Blanch the Bok Choy: Bring a pot of salted water to a boil. Add the bok choy and blanch for 30 seconds until they become bright green but still crisp. Drain and set aside.

Sauté the Mushrooms: Heat 1 1/2 tablespoons of peanut oil in a large pan or wok over medium-high heat. Add the mushrooms and stir-fry for 5-6 minutes until they become golden brown and tender.

Cook the Aromatics: Add the remaining 1 tablespoon of peanut oil to the same pan. Toss in the dried Chinese chili peppers, garlic, and ginger.

Combine Ingredients: Add the bok choy and mushrooms back into the pan. Pour in the sauce mixture and stir everything to coat the vegetables and mushrooms evenly.

Thicken the Sauce: Pour the cornstarch slurry into the pan and continue to stir until the sauce thickens slightly, about 1-2 minutes.

Serve: Sprinkle with sliced green onions and serve hot with steamed rice or noodles for a complete meal.