Scrub the potatoes.  Cut lengthwise into slices, then cut each slice lengthwise into fries.  Be uniform in size - from steak cut to shoestring - choice is yours.  Put the potatoes in a large bowl of cool tap water and refrigerate for at least 2 hours, up to four.

Get all of your equipment in place: high-sided pot on stove with candy thermometer; heat-proof pan (I used Pyrex) to receive first-cooked potatoes, a spider or other straining tool, second pan or bowl with paper towels to receive finished fries.

Heat the oil in the pot over medium heat to 325° F.   Once the temperature is steady, fry in single-layer batches for three to four minutes, stirring frequently and gently, until the fries are limp but still pale.  Remove with a spider or some other skimmer to the first heat-proof tray.

Once all of the potatoes have had their first fry, Increase the heat of the oil to 375° F.

Fry the potatoes again, in small batches, stirring gently and frequently, until golden brown to your preference, 3 to 4 minutes. Remove with the skimmer and drain on clean paper towels. Season immediately with salt and serve hot.