Crispy roast potatoes with salt and vinegar

Preheat oven to 200°C.

Put the vinegar, salt and potatoes into a large saucepan and cover with 4 cups (1L) water. Bring to the boil and cook for 20 minutes, or until potatoes are just tender. Drain into a colander and toss to slightly roughen the edges.

Put the goose fat into a large baking dish and heat in the oven.

Carefully transfer the drained potatoes to the baking tray with the hot fat and toss around to coat the potatoes. Sprinkle with the sea salt and rosemary sprigs. Roast in the oven for 40 minutes, turning occasionally, or until golden brown.