Preheat the oven to 220C/425F (fan).

Peel the potatoes and chop them into chunky pieces a little bigger than a ping pong ball (approx 2 inches/5cm across).

Place the potatoes in a pan and cover with cold water. Place on high heat and bring to the boil, then turn down the heat and simmer for 8-9 minutes until softened at the edges.

Meanwhile, place the lard or duck fat in a large roasting tin and place in the oven for 10 minutes until shimmering hot.

Drain the potatoes in a colander and give them a good shake to roughen up the edges.

Carefully place the potatoes in the baking tin with the hot fat. Turn them over once to coat in the fat and then place them in the oven.

Cook for 30-35 minutes, turning once or twice in the last 15 minutes of cooking, until golden brown and crispy.

Remove from the roasting tin and serve topped with a sprinkling of Maldon salt and some fresh thyme leaves.