Start by preheating your oven to 425°F (220°C) or your air fryer to 400°F (200°C).
If using frozen shoestring fries, spread them out on a baking sheet in a single layer. If making homemade fries, cut potatoes into shoestrings and soak in cold water for about 30 minutes before drying.
Bake the fries according to package instructions, usually around 20-25 minutes, until golden brown and crispy. If using an air fryer, cook for about 15 minutes, shaking the basket halfway through.
While the fries are baking, melt the unsalted butter in a small saucepan over medium heat. Add the minced garlic and sauté for about 1-2 minutes, until fragrant.
Once the fries are done baking, remove them from the oven. Toss the hot fries with the garlic butter mixture, garlic salt, black pepper, and cayenne pepper in a large mixing bowl.
Sprinkle half of the grated Parmesan cheese over the fries and toss again to combine.
Transfer the fries to a serving platter and top with the remaining Parmesan cheese. Garnish with fresh minced parsley and serve immediately.