Place a wok over high heat until hot. Add the peanut oil, swirling to coat the sides. Add the garlic, ginger, and onion. Cook until the onion is soft, about 30 seconds.
Add the carrot, celery, and broth and stir-fry for 2 minutes. Add the baby corn, green onion, peas, mushrooms, and rice, separating the grains of rice with the back of a spoon. Stir well.
Stir in the pepper, soy sauce, oyster sauce, and sesame oil. Cook until heated through, about 2 minutes. Serve garnished with shredded lettuce.