Preheat your oven to 180°C / 350-375°F / Gas Mark 4-5
Use a peeler to peel each potato and discard the skins
Use a knife to cut the potatoes in half, then half again
Bring a medium sized saucepan to the boil with salted water. Note 4
Par boil the potatoes for 5 - 10 mins, they will be soft on the outside but still firm when pierced with a skewer.
Pour duck fat into the base of a large baking dish, place this in the oven and allow to heat for 5 mins
Use oven mits to remove the baking dish from the oven, place on a heat proof service then use tongs to place the potatoes one by one into the duck fat in a flat layer.
Using oven mits again, place the baking dish back into the oven and bake for 20 mins.
Remove from the oven again using oven mits, place on a heat proof surface, and use tongs to rotate each potato in the duck fat so that the other sides are coated. Return the baking dish to the oven for another 25 mins.
Remove from the oven when the potatoes are golden brown and crunchy. Use tongs to remove each potato from the remaining duck fat and let drain.
Sprinkle with salt and serve with gravy (optional)