Sweet Potato and Celery Root Soup
The secret to the not-too-sweet flavor of this velvety soup is celery root, or celeriac. Its light celery-parsley notes balance the sweetness of the potatoes and the pepper bite of the turnips.
Yields about 3 quarts
2 lb. sweet potatoes, peeled and diced (about 5-1/2 cups)
1 lb. celery root, peeled and diced (about 3-1/2 cups)
3/4 lb. purple-top white turnips, peeled and diced (about 2 cups)
3 Tbs. extra-virgin olive oil; more for drizzling
2 medium yellow onions, chopped
1 Tbs. chopped fresh thyme
2 Tbs. sweet sherry or Marsala
4-1/2 to 5 cups homemade or store-bought vegetable or chicken broth (or water)
1/2 tsp. freshly grated nutmeg
1/8 tsp. ground allspice
1/8 tsp. cayenne; more as needed
Put the sweet potatoes, celery root, and turnips in a 6-quart pot. Add 4-1/2 cups water and 1 tsp. salt. Bring to a boil over medium-high heat; then lower the heat to maintain a simmer and cook until completely tender, about 40 minutes.
Meanwhile, heat 2 Tbs. of the olive oil in a 12-inch nonstick skillet over medium-high heat. Add the onions and 1/4 tsp. salt; cook, stirring often, until just beginning to color, about 5 minutes. Stir in the thyme, reduce the heat to low, and cover. Cook, stirring occasionally, until very soft and amber in color, about 20 minutes. Stir in the sherry or Marsala and simmer until the liquid is absorbed, 1 to 2 minutes.
Add the onions, 4-1/2 cups of the broth, the nutmeg, allspice, and cayenne to the pot. Simmer for 5 minutes and then add the remaining 1 Tbs. olive oil. Let cool slightly. Working in batches, purée the soup in a blender. Season to taste with salt and cayenne. If it seems too thick, add the remaining broth.
Reheat the soup if necessary. Ladle into bowls and drizzle some olive oil over each serving.
Make Ahead Tips
The soup may be made up to 3 days ahead and refrigerated; reheat gently before serving. You can also freeze the soup for up to 1 month.
From Fine Cooking 113
, pp. web only
September 1, 2011