Peel and rinse potatoes, then cut them into sticks by cutting the potato in 4 or 5 vertical pieces, and then cutting each piece into sticks.
Place them in a large bowl and cover with cold water. Let them soak for AT LEAST 2 to 3 hours. If you have the time, though, you can pop them in the fridge and let them soak overnight. This is a REALLY important step for super crispy on the outside and soft on the inside fries.
When you're ready to make the fries, drain off ALL the water (I like to pour the potatoes into a colander). Spread out the potatoes in an even layer on 2 baking sheets lined with paper towels. It helps them dry if they're not all piled on top of each other.
Blot with paper towels to dry them. Be sure the potatoes are REALLY dry before frying them.
Heat a few inches of oil in a heavy pot to 300 degrees F. I like to use a candy thermometer to check the temperature.
In 3 or 4 batches, cook the potatoes until soft, 4 to 5 minutes per batch. They should not be brown at this point! You're just starting the cooking process. Remove each batch with a spider (one of my favorite kitchen tools!) and drain on a plate lined with paper towels.
Once all the potatoes have been fried at 300 degrees F, turn up the heat until the oil reaches 400 degrees F.
This is when the true magic (and secret to crunchy, irresistible fries) happens. When the oil is hot, start frying the potatoes in batches again, cooking until the fries are golden and crisp. Remove the potatoes from the oil and drain on paper towels.
Sprinkle generously with Maldon sea salt (or truffle) and fresh parsley or rosemary.