1. Prepare brown rice according to package directions for 4 servings.
2. Meanwhile, heat 1 tablespoon of the oil in large, deep skillet or wok over high heat until almost smoking. Toss beef with 2 teaspoons of the cornstarch in medium bowl. Add to skillet and cook, stirring, until done, 1 to 2 minutes. With slotted spoon, transfer to clean bowl.
3. Add remaining 1 teaspoon oil to skillet. Add garlic, red pepper, and onion; cook, stirring, 30 seconds. Stir in broccoli and Stir-Fry Sauce. Dissolve remaining 1 teaspoon cornstarch in chicken broth; add to skillet and cook, stirring occasionally, until broccoli is tender, 5 minutes.
4. Return beef to skillet with watercress and cook, stirring, 1 minute more. Serve with brown rice. Makes 4 servings.Stir-Fry Sauce::
5. Combine reduced-sodium soy sauce, dry sherry, grated fresh ginger, and sugar in jar with tight-fitting lid. Stir until sugar is dissolved. Refrigerate up to 2 weeks. Shake before using.