1. Preheat oven to 220°C.

2. Cook the potatoes in boiling salted water for 8-10 minutes, or until just tender and a thin knife can pierce through without resistance. Drain the potatoes in a colander and give them a good shake to rough up the edges—this step helps them become extra crunchy when roasted.

3. Place a large baking tray in the oven with the duck fat and heat for 5-10 minutes until hot. Carefully remove the tray from the oven, add the potatoes, and lightly toss them to coat in the hot duck fat.

4. Roast for 20 minutes.

5 Lightly crush the garlic cloves with the side of a small saucepan.

6. After 20 minutes, add the garlic and rosemary to the potatoes. Toss the potatoes gently with a slotted spoon or tongs to mix everything.

7. Roast for another 30 minutes.

8. Turn the potatoes one last time to ensure all sides are golden and crispy. Roast for a further 10 minutes.

Transfer potatoes to a serving dish, leaving behind the excess duck fat. Season generously with flakey salt and enjoy!