Preheat the oven to 425ºF. In a large pan, parboil the potatoes in boiling, salted water for 10 minutes, then drain in a colander, shaking it to chuff up the edges of the spuds.

Heat a large roasting pan on the stovetop over a low heat. (You may need 2 pans.) Add the goose fat or oil and the garlic, orange peel and sage, then fry for 30 seconds. Add the spuds and toss them until well coated.

Place the pan in the oven and cook for 45 minutes or until golden and crisp.