1) Rub the oven potatoes under cold running tap water and drain them on a clean kitchen towel. Don’t peel them. Then with a sharp knife slice them thinly (or use a mandoline slicer like I did).

2) Sprinkle a rectangular oven dish with a little bit of the cold butter and the chopped garlic. Season with some pepper and salt. Then layer the sliced potatoes on top of it.

3) When the first layer of potatoes is finished, sprinkle it with some more butter, garlic, pepper, salt and a small amount of the grated cheese and freshly chopped parsley.

4) Then keep layering the sliced potatoes the same way again. Make sure to keep a handful of grated cheese aside for later. Finish with a layer of potatoes, chopped parsley and butter. Season with a little pepper and salt.

5) Then add the milk.

6) Bake the potato gratin in a preheated oven at 392°F (200°C) for 45 minutes. Then turn off the heat in the end. Remove the potato gratin from the oven. Sprinkle with the remaining grated cheese.

7) Pop the gratin back into the hot oven for another 20 minutes. Then take out the gratin and let it cool for 5 minutes. Serve hot.