Heat a heavy skillet on high for one minute. Add your oil. It should immediately turn hyper-fluid and start moving and shimmering all over that skillet. Move the skillet around to get the oil everywhere.
Add your potatoes in one layer. Leave them alone for a minute. Shake the pan. They should be moving freely. Leave them alone again.
Shake the pan every minute or so to make sure they aren’t sticking.
When they’re good and brown, stir them around. Shake the pan some more.
They will probably take about 8 minutes total.
If you want onions, add them in after about five minutes. Just keep shaking, flipping, browning until they are toasty as a pair of kittycat mittens.
Salt and pepper those puppies and you got it made in the shade.