Prepare the sauce by combining soy sauce, vegetarian oyster sauce, sugar, black pepper, and a splash of sesame oil in a medium bowl. Set aside.

In a separate small bowl, whisk together cornstarch and water until smooth and lump-free. Set aside.

Bring a large skillet filled with water to a rolling boil. Add baby bok choy and cover to steam for one minute.

Heat peanut oil in the skillet over medium-high heat and sear the brown mushrooms for about 3 minutes until golden brown.

Push the mushrooms to one side, add chili peppers, garlic, ginger, and green onions. Stir for one minute until aromatic.

Pour the prepared sauce over the mushroom mixture and stir for thirty seconds, then add cornstarch slurry and cook until thickened.

Remove from heat, transfer to a serving platter and garnish with sesame seeds or cilantro to serve warm.