Pre-heat a heavy cookie sheet (one with sides) in a 400F oven (350-425F is fine - go with whatever your oven needs to be at for anything else you are cooking).
Boil the potatoes in well salted water until just tender - about 15 minutes.
Drain and press lightly on each potato individually to split the skin. This is the only real work in this recipe but it makes all the difference.
Add duck fat to pre-heated cookie sheet (enough to make sure there will be fat to baste - like a tablespoon per 10 small potatoes.
Spoon melted fat over the potatoes. Get some in the nooks and crannies.
Roast them for around 10 minutes. Baste again - maybe shake them up to make sure they brown evenly. Another 10 minutes, baste and shake. Another 10 minutes, baste and shake.
When you are happy with them remove from oven, transfer to a bowl and toss with salt to taste.That's it. It's that easy.