- Heat your oven to 200℃/180℃ fan. Heat the butter and vegetable oil in a small saucepan over medium/medium-low heat. Add the garlic, rosemary and sage and cook, stirring constantly, until the garlic is lightly golden. Keep an eye on it, it’ll look like nothing is happening at first, but the garlic will go from blonde to burnt in a matter of seconds! Drain well, reserving the buttery oil in a small bowl and the garlic-herb mix in another.
- Wash and scrub the potatoes. Using a sharp knife, carefully make vertical slits at 3 mm intervals, three-quarters of the way down each potato, all the way along. Placing the potatoes between the handles of two wooden spoons will make things easier; it will stop you from slicing all the way through.
- Lightly grease a large baking tray. Dip or brush the potatoes with the buttery oil mixture then arrange them on the baking tray in a single layer. Season generously with sea salt and freshly-ground black pepper.
- Bake for 45 mins then brush with more of the buttery oil. At this point, the slices will start to spread out. Brush with the remaining buttery oil, season again (lightly), then bake for a further 30 minutes, or until the potatoes are golden and crispy at the edges.
- Top the potatoes with the fresh parsley and reserved garlic-herb mix. Enjoy!