Method
There is no fancy skill involved in making these crispy fries, but there is a trick. The potatoes are fried twice. The first time cooks them through and makes them tender. The second time, which can be done hours later just before serving, turns them golden brown and deliciously crisp.
Keep in mind that the older the potato, the better it is for making fries. Never make fries with young potatoes as they have not had time to develop sufficient starch.
The size of the fries is a very personal matter. Some people like them very thin and crunchy. Others prefer them quite large so that they can be crispy on the outside and soft in the center. Experiment to find the size you like best. Very thinly cut potato sticks need a shorter frying time, and the thicker ones take a little longer.
Pour enough oil into a deep fryer to reach at least halfway up the sides of the pan but not more than three-quarters of the way up. Heat the oil to 325 degrees F.
Cut the potatoes into sticks 1/2 inch wide and 2-1/2 to 3 inches long. Dry all the pieces thoroughly in a clean dish towel. This will keep the oil from splattering. Divide the potato sticks into batches of no more than 1 cup each. Do not fry more than one batch at a time.
When the oil has reached the desired temperature, fry the potatoes for 4 to 5 minutes per batch. They should be lightly colored but not browned. If your fryer has a basket, simply lift it out the remove the fried potatoes. Otherwise, use a long-handled skimmer to lift out the potatoes. Be sure to bring the temperature of the oil back to 325 degrees F in between batches. At this point the fries can rest for several hours at room temperature until you are almost ready to serve them.
Heat the oil to 325 degrees F. Fry the potatoes in 1 cup batches until they are nicely browned and crisp, 1 to 2 minutes. Drain on fresh paper towels or brown paper bags and place in a warmed serving bowl lined with more paper towels. Sprinkle with salt and serve. Never cover the potatoes to keep them hot as they will immediately turn soft and limp.
Traditional Belgian fries are served with mayonnaise.