1. In a large saucepan cook onion in hot oil over medium heat until tender. Sprinkle flour over onion and stir to coat. Add the asparagus, milk, chicken broth, potatoes, salt and red pepper.
2. Cook and stir until thickened and bubbly; reduce heat. Simmer, covered, for 10 to 12 minutes or just until vegetables are tender, stirring occasionally. Add cheddar cheese, tomato, and sour cream; stir until chese is melted. Makes 4 servings.