Preheat the oven to 190C/170C fan/gas 5. In a large bowl, combine double cream, crushed garlic, melted butter, salt, white pepper, and thyme. Mix well and set aside.

Wash and peel the potatoes, then thinly slice them using a mandolin or a knife.

In an ovenproof dish, layer sliced potatoes, pour some of the cream mixture over them, and add some grated cheese. Repeat the process until the dish is full, ensuring the final layer is cheese.

Bake in the oven for 1 to 1 ½ hours or until the potatoes are cooked through and the top is golden brown.