Ingredients

• 1 cup mayonnaise
• 2 tablespoons tomato paste
• 2 tablespoons finely chopped onion
• 1 tablespoon finely chopped green bell pepper
• 1 tablespoon finely chopped red bell pepper
• 1 tablespoon fresh lemon juice
• 1/4 teaspoon salt
• 4 to 6 cups vegetable oil for deep-frying
• 3 lb russet (baking) potatoes (5 or 6)
• a deep-fat thermometer

Instructions

1. Stir together all sauce ingredients and chill, covered, at least 1 hour to allow flavors to develop. Bring to room temperature before serving.
2. Heat 2 inches of oil slowly in a 5- to 6-quart heavy pot over moderately low heat until thermometer registers 300°F.
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.
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.
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.