1. Deep-fry shrimp as in Basic Deep-fried Shrimp and keep warm. Mince onion.
2. Blend together cornstarch, sherry, soy sauce and stock.
3. Heat remaining oil. Add minced onion and stir-fry until translucent (1 to 2 minutes).
4. Add cornstarch-sherry mixture and cook, stirring, until sauce thickens. Pour over shrimp and serve.