At least 12 hours before frying: heat oven to 350 degrees 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 directly on the oven rack for 45 minutes to 1 hour, until tender or until an instant read thermometer inserted into the center of a potato reads 185 to 195 degrees F.
Cool to room temperature and then refrigerate overnight, unwrapped if possible.
The next day, heat the 2 quarts peanut oil to 375 degrees F in a large Dutch oven fitted with a deep-fry thermometer. (As the temperature crosses 350 degrees F, turn down the heat so that you don't shoot through the target temp.)
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, 2-3 minutes. You'll have to adjust the heat to maintain the oil temperature, so keep an eye on it. Use a spider to fish the fries from the oil to a cooling rack set over paper towels. Sprinkle with additional salt while hot and devour.
Note: since the fries have already been cooked by baking, they're won't be as much bubbling and foaming in the oil, which is nice. Even better: the fries will be ridiculously crisp on the outside while still cream-soft on the inside.