Seafood is ideal for stir-frying. Use firm seafood that will hold together. Shrimp and scallops are just the right size. Cut fish into small chunks or bite-size pieces. Catfish, tuna, salmon and other firm fish cook quickly and remain tender.
In small bowl, combine sherry, soy sauce and sesame oil. Set aside.
Heat 2 tablespoons oil in large skillet over high heat. Add onion and broccoli and stir-fry until crisp tender, about 4 or 5 minutes. Remove vegetables. Heat remaining oil in skillet. Lightly salt and pepper shrimp and add to pan. Stir-fry until cooked through and pink, about 4 to 5 minutes. Stir in sauce, return vegetables to skillet and stir-fry just to heat through, about 1 minute. Serve over rice, if desired. Serves 6 to 8.