Dear Margaret: Thank you so much for your request! We receive dozens of requests each week and try our best. Still, obviously, we don't have time or space to test and run them all. But chef Evan Treadwell of Lido Restaurant graciously provided the recipe you're looking for, which we've adapted below.
Winter vegetable soup
Total time: 1 hour
Servings: 6 to 8
Note: Adapted from Lido Restaurant. White truffle oil is available at select gourmet markets and most cooking supply stores. The restaurant garnishes the soup with whipped crème fraîche and black truffle shavings, though the chef also suggests garnishing with sauteed mushrooms and a drizzle of truffle oil.
2 cups sliced leeks, white part only, cleaned and sliced into 1/4 -inch strips (from about 3 whole)
1/4 cup ( 1/2 stick) butter
2 sprigs thyme
2 bay leaves
4 1/2 cups diced boiling potatoes (from a scant 2 pounds), peeled and diced into 1/4 -inch cubes
1 1/2 cups diced parsnips (3 to 4 whole), peeled and diced into 1/4 -inch cubes
1 celery root (about 1 pound), peeled and diced into 1/4 -inch cubes
1 quart chicken broth, more as desired
Salt and white pepper
1 cup heavy cream
White truffle oil
1. In a medium heavy-bottom soup pot heated over medium-high heat, saute the leeks in the butter until tender, 3 to 5 minutes, stirring frequently, and being careful not to burn the butter. Stir in the thyme and bay leaves and continue to cook until aromatic, about 1 minute.
2. Stir in the potatoes, parsnips, celery root and broth and bring the mixture to a good simmer. Season with one-half teaspoon salt and a pinch of pepper, or to taste. Cook until the parsnips begin to become tender, 15 to 20 minutes. Reduce the heat to a gentle simmer and stir in the cream. Continue to cook until all of the vegetables are tender, an additional 5 to 10 minutes. Remove and discard the thyme sprigs and bay leaves.
3. Purée the soup until smooth using a blender or immersion blender. Strain the soup through a fine mesh strainer and season as desired with additional salt and pepper. Add the truffle oil, a few drops at a time, to taste.
4. Ladle the soup into bowls and serve immediately.
Each of 8 servings: 299 calories; 4 grams protein; 33 grams carbohydrates; 4 grams fiber; 17 grams fat; 11 grams saturated fat; 58 mg. cholesterol; 5 grams sugar; 602 mg. sodium.