Preheat the oven to 170C Fan.

Heat some oil in a large pot over a medium to high heat. Add the sliced onion and cook for a few minutes until it softens.

Chuck in the garlic and chopped thyme and cook for a further minute.

Pour in the double cream and milk, and then add the parmesan, nutmeg, salt, and pepper then stir it well.

Slice the potatoes thinly, approx. 3mm thick. Add them into the pot with the cream, then stir well to split the slices of potato up.

Bring it to a simmer and cook until the cream thickens slightly.

Spoon the potatoes into an oven proof dish, then pour over any remaining cream, leaving a gap of about 1cm at the top.

Bake it for about 45 minutes, or until golden and bubbling. Leave it to stand for a few minutes before serving. Enjoy.