Dissolve bouillon in water. Combine the cornstarch and soy sauce until smooth; add to bouillon. Set aside. Toss beef with garlic, ginger and pepper. In a large skillet or wok over medium-high heat, stir-fry beef in 1 tablespoon oil until meat is no longer pink; remove and keep warm. , Heat remaining 1 tablespoon oil; stir-fry vegetables until crisp-tender. Stir soy sauce mixture and add to the skillet; bring to a boil. Cook and stir for 2 minutes. Return meat to pan and heat through. Serve with rice.