Crispy Double

Using a mandoline or a sharp knife, slice the russet potatoes into thin, uniform fries.

Place the cut potatoes into a large container of cold water. Rinse the potatoes several times, changing the water each time, until the water runs clear. This removes excess starch.

In a large pot, bring 4 quarts of water to a boil. Add 1 tablespoon of kosher salt and 2 tablespoons of white vinegar.

Working in small batches, blanch the fries in the boiling water for exactly 5 minutes.

Remove the blanched fries with a spider strainer and spread them in a single layer on a baking sheet lined with paper towels. Let them steam and dry for 10 minutes.

In a deep pot or fryer, heat the frying oil to 275°F (135°C).

Fry the potatoes in small batches for 3 minutes. They should be cooked through but still pale.

Drain the par-fried potatoes and spread them on a clean baking sheet. Let them cool and rest at room temperature for at least 40 minutes.

Increase the oil temperature to 400°F (200°C).

Fry the potatoes for a final time, again in small batches, for 4-5 minutes or until they are golden brown and crispy.

Drain the finished fries in a paper towel-lined bowl and immediately season with rosemary salt. Toss to coat evenly and serve hot.