To begin, peel the Yukon golds and cut them into even-sized, large chunks.
Add the chunks to a pot of cold water. Bring this pot to a boil and cook the potatoes just about 10 minutes after the boil starts.
While the potatoes boil, place the roasting dish with the duck fat into a preheated 425° oven to get nice and hot.
Next, drain the potatoes into a colander and let any remaining water evaporate. They need to be very dry.
Return the potatoes to the pot, cover with the lid, and give the potatoes a good shake to rough up the outsides of the potatoes.
CAREFULLY, remove the roasting pan from the oven. CAREFULLY, spoon the potatoes into the roasting dish. You want to take your time to avoid any splashing of the oil.
Take care to coat each potato piece in the fat and return to the oven. Roast them at 425° for 20 minutes. Remove potatoes from the oven and CAREFULLY flip each one over.
Return the roasted potatoes to the oven for an additional 15 minutes. Remove this from the oven, flip the potatoes and repeat this for at least 2 more times. The idea is to give each side of the potato time to crisp up.
After the final flip and cook, you should have the most lovely, crispy roast potatoes ever. Let them cool for just a few minutes and top with minced chives, flakey sea salt, and fresh ground pepper.