Wash and peel the russet potatoes if desired. Cut into 1/4–1/3 inch sticks for classic fries. Place cut fries into a large bowl of cold water and soak 30 minutes to 1 hour to remove excess starch (this helps them get crisp).

Dry fries

Drain the fries and spread them on clean kitchen towels or paper towels. Pat thoroughly dry to remove as much moisture as possible; moisture will cause oil to splatter and make fries soggy.

First fry (blanch)

Pour vegetable oil into a heavy pot or deep fryer and heat to 325°F (160°C). If you don't have a thermometer, heat until a small piece of potato bubbles gently but does not brown. Working in batches, fry the potato sticks for 4–5 minutes until softened and pale (they should not brown). Remove with a slotted spoon and drain on a wire rack or paper towels.

Rest

Let the par-fried potatoes rest for at least 10 minutes (or refrigerate up to a few hours). This step firms them and improves final crispness.

Second fry (crisp)

Increase oil temperature to 375°F (190°C). Fry the par-cooked fries in batches for 2–3 minutes until golden brown and crisp. Remove and drain on a rack or paper towels. Immediately sprinkle with 1 tsp salt while hot and toss gently to distribute.

Cajun Seasoning

While fries rest after the first fry (or while oil reheats), mix the cajun seasoning: combine 1 tbs paprika, 1 tsp garlic powder, 1 tsp onion powder, 1 tsp dried oregano, 1 tsp dried thyme, 1 tsp cayenne pepper, 1 tsp black pepper and 1 tsp salt in a small bowl. Adjust cayenne to taste for more or less heat.

Toss fries with seasoning: place hot, drained fries in a large bowl. Drizzle the melted butter over the fries and immediately sprinkle the cajun seasoning evenly. Toss gently but thoroughly so the seasoning coats the fries. Taste and adjust salt or cayenne as needed.

Finish & Sauce

Garnish: transfer seasoned fries to a serving platter or basket. Sprinkle chopped fresh parsley over the top if using for color and brightness.

Serve with extra sauce: provide 1 cup of extra sauce (spicy mayo, remoulade, or ranch) on the side for dipping. If you want the fries sauced like a sandwich side, spoon a little sauce over half the fries at serving time, or serve all sauce on the side per preference.