Preheat oil in a deep fryer or pot to 300°F (150°C). You want it at least 3 inches deep.
Place the prepared potatoes in a large container filled with cold water, submerging them completely. Allow the potatoes to soak for approximately 10 minutes. Gently agitate the potatoes in the water to remove excess starch.
Drain the potatoes in a colander and rinse them thoroughly under cold water for 3 to 4 minutes. Let the potatoes drain for an additional 2-4 minutes to remove excess water and then pat dry with paper towels.
Add a couple of handfuls of the cut potatoes to the hot oil and fry for about 3 minutes. After 90 seconds, gently stir or move the potatoes in the oil for even cooking. Once cooked, remove the fries from the oil and place them on a parchment-paper lined sheet pan.
Turn up the oil temperature to 350°F (180°C).
Add a couple of handfuls of the pre-fried potatoes to the hot oil and fry for 5-6 additional minutes, or until crispy and golden brown on the edges. Fry for an extra minute or 2 for extra crispiness. Drain the fries in the parchment-lined baking sheet to remove excess oil.
Transfer the fries to a bowl and toss them with the cheese, truffle oil, garlic, parsley and salt. Serve immediately.
Notes
Soak the cut potatoes in cold water for about 10 minutes to remove excess starch, which helps achieve a crispier texture.
After soaking, make sure to pat the potatoes dry with paper towels to prevent oil splattering when frying.
Keep the oil temperature consistent throughout the frying process. Fluctuating temperatures can lead to uneven cooking and less crispiness. Adjust the heat as needed to maintain the desired frying temperature.
Fry the potatoes in small batches to avoid overcrowding, which can lead to uneven frying.
After frying, place the fries on paper towels or a wire rack to drain excess oil.
Truffle oil can be potent, so start with a small amount and gradually add more to suit your taste.
Fries are best enjoyed fresh and hot, so serve them immediately after cooking.