Heat oil in heavy large pot over medium-high heat. Add onions; sauté until tender, about 12 minutes. Add garlic; stir 1 minute. Add squash and 5 1/2 cups broth; bring to boil. Reduce heat; cover and simmer until squash is soft, about 40 minutes. Cool slightly.
Working in batches, puree soup in blender until smooth. Return puree to pot. Add 1 teaspoon thyme and orange peel. Thin soup with more broth if desired. Simmer 3 minutes. Season with salt and pepper. (Can be made 1 day ahead. Cool slightly. Cover and chill. Rewarm before serving, thinning with more broth if desired.)
Ladle soup into bowls. Swirl 1 tablespoon Roasted Red Pepper Puree into soup in each bowl. Sprinkle with remaining 2 teaspoons thyme and serve.