Cardoon Soup with Black Truffle Carpaccio Recipe

Name: Cardoon Soup with Black Truffle Carpaccio Recipe
Ingredients: Juice of 2 lemons; 3 pounds cardoon stalks*; 1 tablespoon sea salt, plus more to taste; 3 tablespoons extra-virgin olive oil; 1 medium-sized Vidalia or Spanish onion, quartered and sliced thinly; 1/2 cup dry white wine; 2 cloves garlic, chopped finely; 8 ounces Yukon Gold potato, peeled and cut into ½-inch cubes; 2 1/2 cups vegetable stock; 3 cups water; Freshly ground black pepper, to taste; 8 sprigs Italian parsley; 6 sprigs thyme; 2 tablespoons crème fraîche; 4 teaspoons black truffle carpaccio or truffle oil, for garnish**; 1/4 cup chives, chopped finely, for garnish