1. Pour enough oil into a deep fryer to reach at least halfway up the sides of the pan but not more than three-quarters of the way up. Heat the oil to 350°F.
2. Cut the potatoes into sticks 1/2 inch wide and 2 1/2 to 3 inches long. Dry all the pieces thoroughly in a clean dish towel. This will keep the oil from splattering. Divide the potato sticks into batches of no more than 1 cup each. Do not fry more than one batch at a time.
3. When the oil has reached the desired temperature, fry the potatoes for 4 to 5 minutes per batch. They should be lightly colored but not browned. If your fryer has a basket, simply lift it out the remove the fried potatoes. Otherwise, use a long-handled skimmer to lift out the potatoes. Be sure to bring the temperature of the oil back to 325°F in between batches. At this point the fries can rest for several hours at room temperature until you are almost ready to serve them.
4. Heat the oil to 350°F. Fry the potatoes in 1-cup batches until they are nicely browned and crisp, 1 to 2 minutes. Drain on fresh paper towels or brown paper bags and place in a warmed serving bowl lined with more paper towels. Sprinkle with truffle salt and serve. Never cover the potatoes to keep them hot as they will immediately turn soft and limp.
5. Mix the mayo with Truffle Tapenade in a small bowl and serve immediately.
Optional: Sprinkle with shaved Parmesan cheese and enjoy.
If you are inclined to perfectionism, leave some potatoes to fry halfway through the meal so you can serve them crisp and piping hot.