Cut the potatoes into 3/8-inch fries, rinse them under cold water, and dry them thoroughly.
Mix the paprika, garlic powder, onion powder, oregano, cayenne and salt in a small bowl.
Heat the oil to 325°F and fry the potatoes in 3 batches for 4 minutes until flexible and pale, then drain for 10 minutes.
Raise the oil to 375°F and fry the potatoes again in batches for 2 to 4 minutes until brown and crisp.
Transfer the fries to a large bowl while hot, add half the spice mix, toss and taste before adding more.
