Partially freeze the beef to make it easier to handle and cut. Slice very thinly across the grain into bite size strips. Cook the broccoli and carrots, covered, in boiling salted water for 2 minutes. Drain. Set aside. Mix the cornstarch, sugar and salt. Stir in the soy sauce and the sherry. Set aside.
Preheat a wok or large skillet over high heat. Add oil. Stir fry the broccoli, carrots and onion until tender crisp (about 2 minutes). Remove from the wok. Replenish the oil as necessary. Add half the beef to the HOT oil. Stir fry until browned (2-3 minutes). Remove. Repeat with the remaining beef. Return all the meat to the wok. Add the peas, water chestnuts and bamboo shoots. Stir the soy mixture into the wok. Cook, stirring steadily, until thickened and bubbly. Cook, stirring steadily, another minute or two. Return the broccoli, carrots and onion to the wok. Cover. Cook for 1 minute. Serve over rice.