Slice the ends off the peeled potatoes in order to obtain flat, uniform cuts. Soak peeled potatoes in cold water to prevent oxidation, and dry well before cutting.

Divide each potato into roughly 1” (2.5cm) rounds, and toss with the melted butter, duck fat, herbs, salt, and pepper in a large bowl to coat.

Place the rounds in your largest, deepest, heaviest skillet. Do not overlap the potatoes; any slices that do not fit can be reserved for another batch or simply roasted in the oven. Preheat your oven to 450°F (230°C).

Heat over medium-high heat, cooking the potatoes undisturbed until a deep, brown crust has formed on the underside (this may take as little as 5 minutes, or up to 12).

Turn the potatoes with tongs or a fish spatula, and cook for a further 5-7 minutes on the remaining side.

Pour in the stock and add the garlic. It will seem like too much stock, but it will reduce significantly in the oven.

Transfer the skillet to the middle rack of your oven, and roast for 10-12 minutes, watching carefully to ensure the potatoes do not burn.

Turn the potatoes, and roast for another 10-12 minutes. They are done when a thick, rich brown crust has formed on each potato, and the stock has reduced and become highly concentrated.

Allow to cool for at least 5 minutes and serve warm. The garlic is an extra treat.