1. Cut the leek into 2 1/2 -inch long julienne strips. Using a vegetable peeler, strip off shavings of the sweet potato.
2. In a medium saucepan, heat about 2 inches of the oil over medium-high heat. Add a small handful of the leeks and fry until they are golden and crisp. Drain on paper towels. Fry the sweet potato shavings, a small handful at a time until crisp. Drain on paper towels.
3. In a large bowl, combine the frisée add the Truffle Vinaigrette and toss to combine thoroughly. Divide the salad equally among 10 individual plates, piling it high in the center. Top each salad with some of the leeks, sweet potatoes, and a scoop of the Chèvre Soufflé.