Basic green sauce

1. Cook and stir onions in oil in a 3-quart saucepan until tender.
2. Stir in remaining ingredients except broth and sour cream.
3. Cover and cook over medium heat for 5 minutes, stirring occasionally.
4. Place mixture in food processor workbowl fitted with steel blade or in a blender container; cover and process until smooth, about 1 minute.
5. Return mixture to saucepan; stir in broth.
6. Heat to boiling; reduce heat.
7. Simmer uncovered for 10 minutes.
8. Stir in sour cream.
9. Cover and refrigerate any remaining sauce.
10. Makes about 4 cups of sauce