Set oven temperature to 200oC/400oF/Gas mark 6.
Peel and cut the potatoes in half, place into a saucepan of water, boil and simmer for 5 minutes.
Drain in a colander and tip back into the empty saucepan.
Heat the Goose fat and garlic oil in a microwave for 5 minutes, pour into the potatoes, place the lid back on the saucepan and shake vigorously.
Tip the potatoes and oil onto a hot tray, season and roast in a pre-heated oven for about 1 hour, turning occasionally.