Food.com and the Food Network provide recipes for roasted, salted peanuts in their shells. Food.com's recipe takes 72 hours and 30 minutes to make while the Food Network's recipe only takes 40 minutes.
To make Food.com's peanut recipe, boil 16 cups water, and dissolve 1 cup iodized salt in the water. Add 2 pounds raw peanuts in the shell to the water, and place a pie pan or plate on top of the peanuts to keep them submerged for five hours. Stir the peanuts hourly. After five hours, drain the peanuts, and place them on a cooling rack for two days to dry. Preheat the oven to 350 degrees Fahrenheit, and put the peanuts and cooling rack in the oven for 30 minutes.
To make the Food Network's peanut recipe, preheat the oven to 350 degrees Farhrenheit; meanwhile, rinse and pat dry 2 pounds in-shell raw peanuts. Combine 2 tablespoons peanut oil with 1-2 tablespoons kosher salt. Toss the peanuts with the mixture. Spread the peanuts into a single layer over baking sheets and bake for 30 minutes. Allow the peanuts to cool slightly before eating.
If the peanuts are being used for eating out straight out of the shell, it is recommended to use Virginia or Valencia peanuts. However, if the peanuts are going to be used for peanut butter, due to the higher oil count, Spanish peanuts are recommended.