Preheat the oven to 200°C (Gas mark 6/390°F). Lightly brush a baking tray with a little olive oil.

Wash the potatoes under cold running water, drain and gently pat dry with a clean tea towel.

Carefully cut thin slices ¾ of the way into each potato, being careful not to cut all the way through.

Place the potatoes on the oiled baking tray and brush all over with some of the oil.

Season well with salt and pepper before popping in the pre-heated oven to bake for 20 minutes.

As soon as you’ve put the potatoes in the oven, finely chop the garlic and add to the remaining oil, along with the chopped rosemary. Stir to combine then leave to infuse as the potatoes cook.

Finely grate the Gruyère cheese.

After 20 minutes in the oven, remove the potatoes and brush all over with the garlic infused oil.

Using a small spoon, carefully separate some of the potato slices and push the remaining garlic and rosemary between them.

Top each potato with some of the grated cheese until you’ve used it all up.