Preheat the oven to 220˚C/400˚F/Gas mark 6. Place the goose fat in a roasting tray and put it into the oven to heat.

Peel the potatoes and cut them into halves and quarters so they’re roughly the same size for even cooking.

Place the potatoes in a pot and fill up with water until covered. Add a good pinch of sea salt. Bring the pot to the boil over a high heat and simmer for about 7-10 minutes. The potatoes should be cooked on the outer edge but still raw on the inside, you can check this by piercing with a fork.

Drain the potatoes and then place back in the pot. Give them a vigorous shake for 30 seconds or so to roughen the outsides.

Remove the tray from the oven. Tumble the potatoes into the hot goose fat and toss each one to coat before sprinkling with a generous amount of sea salt. Add the garlic and rosemary to the tray.

Roast for 45-50 minutes until golden and crisp.