Preheat oven to 375°F. Bring a large pot of water to a boil.
Put shortening in a large shallow baking dish and place on top rack of oven as it heats. In a large saucepan, cover potatoes with boiling water, add 1 tsp. salt and simmer over low heat for 10 minutes. Drain potatoes and return to pot. Cover pot and, wearing oven mitts, hold lid on firmly and shake pan up and down 2 or 3 times to roughen edges of potatoes.
Remove hot baking dish from oven and place over 2 burners on medium-high heat. Carefully transfer potatoes to dish and baste them with melted shortening. Return dish to oven and roast potatoes for 30 minutes, basting once during roasting time.
Raise oven temperature to 425°F. Using tongs, turn potatoes over and continue to cook until golden brown and crispy, about 20 to 30 minutes longer, turning them again halfway through so that all sides get crispy and brown. Remove potatoes from shortening, drain on paper towels, season with salt and pepper and serve immediately.