Cooking time: 1H10

Add the optional herb or spice for the last 20 minutes of cooking.

1. Preheat the oven to 180 °C / 350 °F. Place the potatoes in a large saucepan, cover with water, season with salt and bring to the boil. Cook for 10 minutes until they are still firm yet easily pierced with a fork. Drain well.then drain well.
2. Heat the oil and butter in a large roasting tray in the oven until just hot. Tumble in the potatoes and crush gently with the back of a fork to burst the skins, turning in the hot oil. Sprinkle with salt and pepper.
3. Separate the cloves of garlic from the bulb but leave them unpeeled. Add to the potatoes.
4. Roast for 1 hour, tossing occasionally, until crisp and golden.
5. Spoon into a serving dish. Scatter with lemon zest to serve.