Preheat your oven to 350 degrees
Clean the skin of your potatoes. Place them into the oven directly on the rack
Bake for 45 minutes to an hour or until the potato can be pierced with a fork.
Allow potatoes to cool. Place in the fridge for at least 12 hours.
Heat your oil in a cast iron Dutch oven or other heavy bottom pan to 375 degrees. Use a fry/candy thermometer or infrared thermometer to monitor the temperature.
While oil is heating, cut the fries to about ½ inch thickness leaving the skins on. Important to try and keep the fries as uniform size as possible for even cooking.
When oil is ready, fry 8-10 fries at a time until golden brown and crispy about 2-3 minutes.
Adjust your heat higher and lower to keep the oil temperature as close to 375 as you can.
Remove the fries to a sheet pan lined with paper towl and cooling rack on top. on the pan. Sprinkle with salt to taste right away.