- 6 tablespoons unsalted butter
- 4 medium onions, thinly sliced
- 3 pounds turnips, peeled and thinly sliced
- 1 1/2 pounds baking potatoes, peeled and thinly sliced
- 6 cups chicken stock or canned low-sodium broth
- 1/4 teaspoon freshly grated nutmeg
- 1/4 cup finely shredded basil, for garnish
- In a large heavy stockpot or casserole, melt the butter until it foams. When the foam subsides, add the onions and cook over moderate heat until softened but not browned, about 5 minutes. Add the turnips and potatoes and stir to coat with the butter. Add 2 teaspoons of salt, cover and cook over low heat, stirring occasionally, until tender, about 20 minutes.
- Stir in the chicken stock and bring to a simmer. Cover partially and cook over moderate heat until the vegetables are very tender, about 10 minutes.
- Working in batches, puree the soup in a blender until perfectly smooth. Return the soup to the pot and season with salt and the nutmeg. Ladle the soup into shallow bowls and garnish with the basil before serving.
The soup can be refrigerated overnight.