In a small bowl, combine cornstarch and broth until smooth. Stir in the soy sauce, hoisin sauce and sesame oil; set aside. In a large nonstick skillet or wok, stir-fry beef in 1-1/2 teaspoons hot olive oil until no longer pink. Remove and keep warm., In the same skillet, stir-fry the onions in remaining olive oil until crisp-tender, 3-4 minutes. Stir cornstarch mixture and add to the pan. Bring to a boil; cook and stir until thickened, about 2 minutes. Reduce heat; add beef and heat through. Serve with rice.