Preheat the oven to 450 F.Place the sliced potatoes in a pot of water, covered by about an inch of water. Depending on the thickness of your fries, you'll want to boil them for just 3-5 minutes. Start the timer once the potatoes start boiling. Be careful not to boil them for too long. It's better to under-boil than to over-boil. You don't want them to be really limp, but just barely starting to become tender.Immediately drain the potatoes and place them in a bowl of ice water. Let them cool for 2-3 minutes, then pour them into a colander to thoroughly drain.
Blot the potatoes with a clean dish towel or paper towels and transfer them to a large bowl. Pour the tallow or oil over the sliced potatoes and toss to thoroughly coat the potatoes. Line a baking sheet and place the potatoes on it in a single layer.Bake on the middle rack for 15 minutes, then use a spatula to carefully turn over the fries. Continue baking for another 10-15 minutes or until the fries are golden and crispy. The length of time will vary depending the size of your fries and how long they were parboiled.Remove the fries from the oven and immediately, while they're still hot (so the salt adheres), sprinkle them with salt and give them a shake to evenly coat. Serve them immediately.