In a small bowl, whisk together all sauce ingredients until cornstarch is dissolved. Set aside.
Heat oil in a large wok or skillet over high heat until smoking.
Add minced garlic and stir-fry for 30 seconds until fragrant and softened.
Add sliced protein and cook for 3-4 minutes, stirring frequently, until cooked through.
Add onions and carrots first, stir-fry for 2 minutes.
Add celery and mushrooms, continue cooking for 2 minutes.
Add bean sprouts and bok choy, stir-fry for 1-2 minutes until vegetables are tender-crisp.
Give the sauce mixture a quick stir and pour into the wok.
Stir constantly for 1-2 minutes until sauce thickens and coats all ingredients.
Taste and adjust seasoning with salt and pepper as needed. Serve immediately over rice.