Peel the potatoes, leave whole if they are small, cut any large potatoes in half or quarters.
Put the potatoes into a large saucepan of cold salted water. Bring up to the boil and boil for exactly 6 minutes.
Drain in a colander and allow to steam dry for a few minutes.
Toss in the colander to rough up the potatoes. Transfer to a large bowl.
Shake over the flour, salt and pepper. Toss well to coat the potatoes.
Spoon over 30g of the duck fat and the Ginger infused oil and toss to coat evenly.
Line a tray with baking paper. Lay the potatoes in a single layer on the tray and place in the freezer. When frozen transfer to a freezer bag. They can be frozen for up to 3 months.
When ready to cook heat the oven to 200℃. Pour the remains 40g of duck fat onto a baking tay and place in the oven. When the fat is sizzling, carefully add the potatoes and roast for 25 minutes.
Remove the tray from the oven and increase the heat to 220℃. Turn over the potatoes and spoon over fat from the tray to coat. Return to the oven for a further 40 minutes or until golden and crisp.