Cook asparagus in boiling water for 3 minutes or until crisp-tender. Plunge into ice water, drain. Cook pasta al a dente. Drain, reserving 1/4 cup cooking liquid. Combine pasta and vegetables.
Combine cheese, salt, pepper and eggs with a whisk in separate bowl and gradually add hot cooking liquid, stirring constantly. Cook bacon until crisp. Remove and add to pasta mixture, reserving 1 tablespoon drippings. Cook bell pepper and garlic and mushrooms (optional) in drippings for 4 minutes. Add pasta mixture and cook until thoroughly heated. Remove from heat and stir in egg mixture. Return to low heat and cook for 3 minutes, stirring constantly. 4 servings