In a small bowl, combine 1 tablespoon soy sauce, 1 tablespoon sherry, garlic powder and 1 tablespoon cornstarch. Set aside.
In a small saucepan, combine water, bouillon and minced ginger. Bring to a boil; simmer 10 minutes. Let cool. Add hoisin sauce, 1 1/2 tablespoons soy sauce, 1 1/2 tablespoons sherry, 1 1/2 tablespoons cornstarch and red pepper flakes. Set aside.
Heat wok to 325Â°. Add oil and stir-fry the meat about 2 minutes.
Add onion and garlic; continue to stir-fry about 2 minutes.
Add celery and cook for 1 minute.
Add sweet pepper, snow peas and mushrooms, if desired. Stir-fry 2 more minutes.
If desired, add sprouts and cook 1 minute.
Combine liquid mixtures and pour sauce over meat and veggies. Stir until thickened. Serve over hot cooked rice.