Fill a large pot with cold water. Peel the potatoes and drop them into the cold water to prevent them from browning.
Cube the potatoes into large chunks and drop them back into the water. Drain and rinse the potatoes a few times, then drain the water completely.
Fill the pot with chicken stock, covering the potatoes completely. Season the pot with a few teaspoons of salt.
Bring the chicken stock to a rolling boil over high heat. Once the stock is boiling, set a timer for 10 minutes. The potatoes should be soft on the outside, but slightly firm on the inside. Drain the potatoes.
Preparing the Duck Fat:
While the potatoes are cooking, prepare the duck fat for roasting. Place a large roasting pan with tall sides into the preheated oven and heat the pan for 4 to 5 minutes, until it’s super-hot.
Carefully remove the roasting pan from the oven and add 5 to 6 tablespoons of duck fat, along with the fresh thyme, rosemary, and garlic.
Place the roasting pan back into the oven for about 5 minutes, until the duck fat is hot, and the fresh herbs and garlic are sizzling.
Roasting Instructions:
Add the cooked, drained potatoes into the hot duck fat. Use a spatula to toss the potatoes until they’re well coated. Spread the potatoes in a single layer, spacing them out slightly.
Roast at 425°F for 25 minutes. Remove the roasting pan from the oven, remove the herbs and garlic and discard; toss the potatoes, then return to the oven.
Continue to roast the potatoes, tossing every 15 to 20 minutes, until they are a rich, golden-brown color all over and crispy.
Remove the potatoes from the oven and transfer them into a serving bowl. Season to taste with salt and pepper, then garnish with fresh thyme or rosemary. Keep the potatoes warm until ready to serve. Don’t cover the potatoes, as this will cause the outside to lose its crispiness.