1. Shell and devein shrimp. Mince ginger root; then combine with sherry and soy sauce. Add to shrimp and toss. Let stand 15 minutes, turning occasionally.
2. Dice green pepper, onion and celery. Blend cornstarch and cold water to a paste.
3. Heat oil. Add shrimp and stir-fry until pinkish (2 to 3 minutes). Remove from pan.
4. Heat remaining oil. Add salt, then diced vegetables; stir-fry to soften slightly (1 to 2 minutes).
5. Stir in stock and heat quickly. Then cook, covered, 2 to 3 minutes over medium heat.
6. Return shrimp; stir in only to reheat and blend flavors (about 1 minute). Then stir in cornstarch paste to thicken, and serve at once.