- 3 sweet potatoes
- 4 potatoes, peeled and quartered
- 1 large onion, thinly sliced
- 2 cloves garlic, minced
- 1 tablespoon olive oil
- 1 tablespoon butter
- 10 cups water
- 1 1/2 tablespoons all-purpose flour
- 1/4 cup chicken broth
- 3/8 cup buttermilk
- 1 teaspoon freshly grated nutmeg
- 1 teaspoon ground ginger
- 1 teaspoon ground white pepper
- 1 teaspoon dried thyme
- 1/2 teaspoon ground cumin
- salt to taste
- ground black pepper to taste
- Roast sweet potatoes in 450 degree F (230 degrees C) oven for 30 minutes. Remove from oven and slice open, allowing to cool while assembling rest of soup.
- Saute onion and garlic in olive oil and butter until soft and slightly browned. Add potatoes to pot and saute 1 minute. Stir in flour. Deglaze pan with broth, scraping up brown bits. Add water and sweet potato flesh. Bring mixture to a boil and reduce heat to medium low. Simmer partially covered for approximately 30 minutes or until vegetables are tender. (Liquid will have reduced to approximately 8 cups.)
- Remove from heat and puree soup in batches in blender or directly in pot with hand-held blender.
- Return soup to pot and re-heat over low heat. Add buttermilk, nutmeg, ginger, white pepper, thyme, cumin, and salt and pepper to taste, stirring well.