Step 1

PreparationMake sauce: Stir together all sauce ingredients and chill, covered, at least 1 hour to allow flavors to develop. Bring to room temperature before serving.

Step 2

Make fries: Heat 2 inches of oil slowly in a 5- to 6-quart heavy pot over moderately low heat until thermometer registers 300°F.

Step 3

While oil is heating, peel potatoes, then cut lengthwise into 1/3-inch-thick sticks and submerge in a large bowl of ice and cold water. Rinse potatoes in several changes of cold water in bowl (more ice isn't necessary) until water is clear. Drain in a colander and spread potatoes out in 1 layer on several layers of paper towels to drain, then pat dry.

Step 4

When oil is ready, increase heat to moderately high and fry potatoes in 4 batches, turning, until just cooked through but still white, about 3 minutes. (Return oil to 300°F between batches.) Transfer as fried with a slotted spoon to dry paper towels to drain. Cool potatoes to room temperature, about 30 minutes.

Step 5

Reheat oil over moderately high heat until thermometer registers 375°F. Fry potatoes again in 4 batches, turning, until deep golden, 3 to 4 minutes. (Return oil to 375°F between batches.) Transfer as fried with a slotted spoon to dry paper towels to drain briefly, then season with salt and serve immediately, with sauce for dipping.

Step 6

Cooks' notes:•Sauce can be chilled up to 1 day. Bring to room temperature before serving.

Step 7

•Potatoes can be cut, but not fried, 6 hours ahead and kept submerged in bowl of cold water.

Step 8

•Fries can stand at room temperature between first and second frying up to 2 hours.