Preparation Heat oil in heavy large saucepan over medium heat. Add onion, bell pepper and garlic and sauté until onion is tender, about 10 minutes. Mix in tomatoes with their juices, chilies and thyme. Reduce heat to low and simmer until vegetables are very soft, about 10 minutes. Add beans and 2 cups chicken broth. Puree soup in batches in processor or blender until smooth. Return soup to pot. (Can be prepared 4 days ahead. Cover and refrigerate.) Bring soup to simmer. Thin with more broth if necessary. Season to taste with salt and pepper. Garnish with sour cream and sliced green onions.
Preparation Heat oil in heavy large saucepan over medium heat. Add onion, bell pepper and garlic and sauté until onion is tender, about 10 minutes. Mix in tomatoes with their juices, chilies and thyme. Reduce heat to low and simmer until vegetables are very soft, about 10 minutes. Add beans and 2 cups chicken broth. Puree soup in batches in processor or blender until smooth. Return soup to pot. (Can be prepared 4 days ahead. Cover and refrigerate.) Bring soup to simmer. Thin with more broth if necessary. Season to taste with salt and pepper. Garnish with sour cream and sliced green onions.