Start by preheating your oven to 180°C (160°C fan) or 350°F.

Peel your potatoes and slice them thinly, aiming for about 3mm thickness.

In a sauté pan, heat a splash of butter or oil over medium heat and sauté the sliced leeks for 5-7 minutes until soft.

In a mixing bowl, combine double cream, whole milk, crushed garlic, salt, pepper, and nutmeg, and whisk until smooth.

Grease your baking dish and start layering sliced potatoes, followed by sautéed leeks until all ingredients are used.

Pour the creamy sauce over the layers ensuring it seeps down.

Sprinkle your chosen cheese on top.

Cover the dish with foil and bake for 45 minutes, then remove foil and bake for an additional 15-20 minutes.

Let the gratin cool for a few minutes before serving.