- Spray a large saucepan with nonstick cooking spray. Add onion and cook over medium-high heat for 5 minutes until lightly brown, stirring often.
- Stir in tomatoes, peppers, garlic, oregano, and salt and cook for a few more minutes.
- Pour mixture into a blender container, cover with a tight fitting lid, and blend until smooth.
- Place mixture back into saucepan. Bring to a boil, and then simmer over medium heat for 5 minutes.
- Add crisp tortillas to saucepan; cook for 2 to 3 minutes more.
- Sprinkle with cheese then cover and let stand for a minute or so more to melt cheese.
- Serve immediately, topped with cilantro, if you like.
Makes 4 servings - 1 cup per serving.