01 - Soak cut potatoes in cold water for at least 30 minutes to remove excess starch. Drain and pat dry thoroughly.
02 - Heat vegetable oil in a deep fryer or large heavy pot to 350°F (175°C). Fry potatoes in batches for 3 to 4 minutes until pale and tender but not browned. Remove and drain on paper towels.
03 - Increase oil temperature to 375°F (190°C). Fry potatoes again in batches for 2 to 3 minutes until golden and crispy. Drain well.
04 - Melt butter (if using) over low heat in a large skillet. Add minced garlic and sauté for 1 minute until fragrant without browning.
05 - Add hot fries to the skillet and toss with garlic, parsley, salt, pepper, and Parmesan cheese (if using) until evenly coated.
06 - Serve immediately while hot and crispy.