How to cook
Peel the potatoes and cut them into 0.5″ x 0.5″ (1 cm x 1 cm) sticks. Soak them for a little while in cold water in order to get rid of some of the starch, and then drain and dry them well on paper towels.
Heat oil in a deep fryer at 320°F (160 °C), then put a handful of potatoes in to fry. Do not add too much, so that the temperature of the oil doesn't drop excessively.
Fry for a few minutes (4-8 minutes), depending on the variety of potatoes, until they become pale - gold, while stirring from time to time, to prevent them from sticking. Remove and leave on a paper towel for about 30 min to drain well. Do the same with the remaining potatoes.
Before serving, heat the fryer to 374°F (190 °C) and put all the potatoes in to fry for 2 minutes until crispy and golden - brown. Serve the fried potatoes immediately, sprinkled with salt and mayonnaise if desired. If you wish, sprinkle with grated feta cheese.