Halve or quarter the yukons, depending on how small they are. If you have full sized yukon golds, then cut into large bite size pieces. Your goal is to have almost no potatoes that are not cut at all (though it works ok if you have tiny ones, and they are yummy sometimes) but also big enough to hold their shape and not disintegrate into mashed potatoes.
Boil in salted water until fork tender. Important! if you over-cook them, you'll get mush in the end, though still tasty. If you under cook them, then it is almost as if you didn't boil at all. Still good, just different.
Drain off the water entirely - pot should be semi-dry from the heat.
Add butter - a whole stick if you have a LOT of potatoes, less (maybe) if you are serving just two people…
Stir vigorously with a blunt instrument, like a wooden spoon. The potatoes should end up “distressed” and absorbing plenty of butter on the outside edges, plus a fair amount of potato-starch-butter sludge covering.
Transfer to a large, flat oven dish so the potatoes are in a single layer more or less.
Bake at high temperature (375°-450° depending on how much of a hurry you are in) until the edges are golden brown and crispy.
Serve hot or warm and don't burn yourself eating them too soon out of the oven.