Classic bistro-style pommes frites (the Belgian version of fries) are served with mayonnaise as a dipping sauce.
Peel potatoes if desired; cut into 1/2-inch-thick matchsticks. Place in a bowl of cold water to soak for 10 minutes.
Heat oil in a large saucepan (at least 5 quarts) to 325 degrees. Remove potatoes from water; dry very well with paper towels. Add potatoes in batches to oil; blanch for 2 minutes (potatoes will not take on any color). Drain well; transfer to pans lined with paper towels to cool completely.
Raise heat of oil to 375 degrees. Heat oven to 250 degrees. Add potatoes to oil in batches; fry until golden, about 3 minutes. Drain well; place on a rimmed baking sheet. Sprinkle with salt; keep warm in oven while frying remaining potatoes. Serve immediately.
Make sure to use at least a five-quart saucepan so the oil won't bubble over.