In a small bowl, combine soy sauce, lemon juice, cornstarch, brown sugar, garlic and pepper. Set aside.
Heat 1 T. canola oil in lge. skillet or wok over med. high heat. Add beef and stir fry until almost cooked through, about 2 minutes. Transfer beef to a plate and cover to keep warm.
Heat remaining oil in skillet. Add onion and stir fry for 5 minutes. Cut broccoli into florets (should yield about 4 cups) and add to skillet with 1/2 cup water. Bring to a boil, cover, reduce heat and simmer for 3 minutes.
Return beef to skillet with soy sauce mixture, add ginger. Bring to boil and cook, stirring constantly, until sauce thickens about 2 minutes. Serve hot.