Cut the asparagus spears into one-inch pieces and steam them lightly. Mix half cup water with the dry boullion; reserve. Mix the cornstarch and one teaspoon of water; reserve. Heat oil in a wok or large frying pan over medium heat. Add the asparagus, mushrooms, salt and pepper; stir fry for about 1 minute. Stir in the bouillon mixture and heat to boiling. Stir in the cornstarch mixture. Cook and stir until thickened (about 15 seconds). Serve as desired.