In a small bowl, combine the first 6 ingredients until smooth; set aside., In a large skillet or wok, stir-fry beef in 1 teaspoon oil until no longer pink, 3-4 minutes. Remove with a slotted spoon and keep warm., Stir-fry vegetable blend and garlic in remaining oil for 3 minutes. Stir cornstarch mixture and add to the pan. Bring to a boil; cook and stir until thickened, about 2 minutes. Add beef; heat through. Serve with rice.