Tomatillo squash bisque

1. In a large saucepan, heat oil and butter.
2. Add garlic and onions; saute until softened.
3. Add squash, chiles and tomatillos, stirring until coated and heated through.
4. Add chicken broth; bring to a boil, then cover and simmer for about 20 minutes or until squash is tender.
5. Tear or shred tortillas into pieces and add to soup mixture.
6. Stir in lime juice and cilantro leaves.
7. In a blender or food processor, blend soup in batches until pureed and smooth.
8. Return to saucepan and heat through.
9. Add salt and pepper to taste.
10. Serve hot accompanied with a dollop of sour cream and a few crumbled tortilla chips and cilantro leaves.
11. This is a thick soup; if you prefer it thinner, add more chicken broth