Wash and cube potatoes. Soak in water 30 minutes to an hour. Remove from water and drain potatoes well.
Add 1/4 cup oil to a cast-iron skillet and heat on medium to medium-low. Add just enough potatoes to make one layer in skillet liberally salt and pepper. (You will have to cook in batches or use two pans.) Cook on one side, undisturbed, until browned. This will take 12 to 15 minutes.
Turn with a spatula and cook until browned and cooked through. (Add more oil if necessary.) When potatoes are browned as much as you like, remove them from the pan and cook the second batch.
Serve warm.*You can use red potatoes, but I'd peel them if you do.