Combine the salt, pepper, and herbs in a large bowl. Pour the oil into a large cast iron skillet and set over medium-high flame or charcoal grill. When the oil reaches a slight smoke, add the potatoes in a single layer and fry until they get nice and crackled on all sides. Cover the potatoes completely with the salt mixture, and cook for about 1 hour until the salt forms a cooked crust and the potatoes are tender. Break open the crust to serve.