Begin by peeling and cutting 500 grams of potatoes into equal cubes. Place the cubes in a large pot and cover them with salted water. Bring the water to a boil over high heat, then reduce to medium and simmer for about 15-20 minutes, or until the potatoes are fork-tender. Drain the potatoes and let them cool for a few minutes.

Once the potatoes have cooled slightly, transfer them to a mixing bowl. Using a potato masher, mash the potatoes until they are completely smooth and free of lumps.

Incorporate flavor by adding freshly grated Parmesan cheese, black pepper, and 4 tablespoons of potato starch to the smooth mashed potatoes. Mix thoroughly until all ingredients are well combined.

To shape your fries, divide the potato mixture into two equal portions. On a floured surface, roll each portion into a rectangle about ½-inch thick. Slice the rectangles into strips, mimicking the shape of traditional fries.

In a deep frying pan or heavy-bottomed pot, heat 2–3 inches of oil to 350°F (175°C). Drop a small piece of potato into the oil to check if it's ready.

Once the oil is hot, gently lower a batch of the shaped potato strips into the oil. Fry for about 5-7 minutes, turning occasionally, until they are golden brown and crispy.

After frying, carefully remove the crispy mashed potato fries from the oil using a slotted spoon. Drain them on a wire rack placed over paper towels.