Preheat the oven to 220°C (425°F)/200°C (425°F) fan/Gas 7.

Put the potato chunks in a pan of cold salted water. Bring to the boil and boil for about 5 minutes until the potatoes are starting to soften around the edges. Drain in a colander until completely dry, tip back into the pan and shake to rough up the edges. Sprinkle in the semolina and shake again until coated.

Preheat a roasting tin in the oven until hot. Add the goose fat and oil and heat for 5 minutes until smoking. Add the potatoes and turn them in the fat until coated. Return to the oven and roast for about 45–55 minutes until the potatoes are golden brown and crisp, turning them over halfway through the cooking time. Serve piping hot.

Prepare ahead: Can be roasted up to 12 hours ahead. Before serving, reheat in a hot oven for 15–20 minutes – no need to add extra fat.