Start by washing, peeling, and cutting the russet potatoes into ¼ inch sticks. You can use a sharp knife or a mandolin slicer for even and consistent cuts.
Rinse the potato strips in cold water to remove excess starch. This helps the fries become crispier during frying. After rinsing, pat them dry thoroughly with a clean kitchen towel or paper towels.
In a large, deep pot or a deep fryer, heat the vegetable oil to 325°F (160°C). Use enough oil to submerge the fries completely.
Carefully add a batch of potato sticks to the hot oil, making sure not to overcrowd the pot. Fry them for about 4-5 minutes, or until they are lightly golden but still slightly soft in the center. Remove them from the oil and drain on paper towels.
Increase the oil temperature to 375°F (190°C).
Once the oil is at the higher temperature, return the partially fried potato sticks to the hot oil in batches. Fry for an additional 2-3 minutes or until they are golden brown and crispy.
Use a slotted spoon or a wire mesh strainer to remove the double-fried fries from the oil and transfer them to a plate lined with paper towels to drain any excess oil. Sprinkle with salt immediately while they are still hot.
Serve your fries hot and crispy. You can enjoy them with ketchup, mayonnaise, or your favorite dipping sauce.