Cut potatoes into quarters and boil for 15-20 mins until soft, then drain
Add goose fat or butter to large baking dish
Add the potatoes, some salt and roast at 200 degrees C for 25 mins
Meanwhile, add the garlic, rosemary, olive oil and salt to a small bowl and mix
Pour the dressing over the partially roasted potatoes, coating as much as possible by moving the potatoes around the baking dish
Roast for a further 20 mins at 200 degrees C