In a small saucepan cook mushrooms in margarine or butter until tender. Stir in flour, Worcestershire sauce, salt, and pepper until blended. Add milk all at once. Cook and stir until thickened and bubbly, then cook and stir for 1 minute more.
Add cheese and stir until melted. Gently stir in egg slices. Cover and cook 1 to 2 minutes longer or until egg is heated through.
Spoon over toasted English muffin. Top with bacon pieces. If desired, garnish with pimiento and serve with fresh fruit. Makes 1 serving.