At least 12 hours before frying, heat oven to 350°F and position rack in top half of the oven. Set an empty sheet pan on a lower rack.
Using a dinner fork or paring knife, poke several holes in the potatoes to allow water vapor to escape during cooking. Coat each potato lightly with 2 teaspoons of the peanut oil and sprinkle generously with salt.
Bake the potatoes directly on the oven rack until tender and an instant-read thermometer inserted into the center of a potato reads between 185°F and 195°F, 45 minutes to 1 hour.
Cool to room temperature and then refrigerate overnight, unwrapped if possible
The next day, add the remaining 2 quarts peanut oil to a large Dutch oven fitted with a deep-fry thermometer. Place over medium-high heat until the oil reaches 375°F.
Slice the cold potatoes into half-inch-thick batons, leaving the skin attached.Boost the heat slightly before adding the first fries and cook 8 to 10 at a time until golden brown and delicious, 2 to 3 minutes. Keep an eye on the oil temperature — you’ll have to adjust the heat to maintain 375°F. Use a spider strainer to fish the fries from the oil and place on a cooling rack set over paper towels. Sprinkle with additional salt while warm and devour.