This recipe is adapted from the classic French frenseuse, a turnip and potato soup enriched with egg yolks and heavy cream. Select turnips with firm, unblemished flesh. The addition of a few shavings of fresh black truffle, and a star-shaped crouton makes this an unforgettable course.
6 tablespoons unsalted butter
2 leeks, white part only, chopped
1 pound Idaho potatoes, peeled and diced
1 1/2 pounds white turnips, peeled and diced
2 tablespoons all-purpose flour
3 quarts Homemade Chicken Stock Homemade Chicken Stock (http://www.marthastewart.com/261561/homemade-chicken-stock), or canned low-sodium chicken broth, skimmed of fat
Salt and freshly ground black pepper
1/2 cup heavy cream
4 large egg yolks
Star-shaped croutons, for garnish (optional)
1 black truffle, shaved, for garnish (optional)
Melt 4 tablespoons butter in a large pot over medium heat. Add leeks, and cook until soft, about 5 minutes. Add potatoes and turnips, stirring to combine. Cover, and cook for about 10 minutes. Sprinkle flour over vegetables, stir to cover evenly, and cook for 1 minute. Add stock, season with salt and pepper to taste, and simmer until vegetables are tender, about 20 to 30 minutes.
With a slotted spoon, remove vegetables from pot, and place them in a food mill. Puree vegetables, and return them to pot. In a small mixing bowl, whisk together heavy cream and yolks. Temper egg mixture by adding 2 cups of soup to the bowl, stir to combine. Add egg-soup mixture to soup pot, and stir to combine. Bring to a simmer, and serve garnished with croutons and truffle shavings.