Boil the potatoes

• Peel the potatoes and cut them into large chunks.
• Place them in a pot of salted water and bring to a boil.
• Cook until just tender, then drain well in a colander.

Shake the potatoes

• Leave the drained potatoes in the colander or pot to steam dry.
• Shake them vigorously so the edges roughen up and mashed bits form.

Heat the fat

• Pour the vegetable oil or duck fat into a baking dish.
• Heat it in the oven until shimmering hot.

Roast the potatoes

• Carefully add the shaken potatoes to the hot fat and turn to coat.
• Season with salt and roast, turning occasionally, until deep golden and crisp.

Serve

• Transfer the roast potatoes to a serving dish and sprinkle with a little more salt.