Ingredients

• 4½ lb – 2 kg waxy potatoes (about 9 medium)
• 2½ cups – 600 ml heavy cream (thickened)
• 1½ cups – 375 ml full-fat milk
• 1 cup – 100g Gruyère cheese (or Swiss), measured ungrated then freshly grated
• 1 small garlic clove, minced
• ¼ tsp freshly grated nutmeg
• 1½ tsp fine sea salt (or to taste)
• ½ tsp freshly ground black pepper
• A few fresh or dried thyme leaves (optional, scattered between layers)

Steps

• Step 1

  Preheat oven to 350°F – 180°C.

• Step 2

  In a jug or mixing bowl, combine cream, milk, nutmeg, salt and pepper. Mix well.

• Step 3

  In a large saucepan, add minced garlic and pour in the milk and cream mixture. Warm gently over medium-low heat.

• Step 4

  Peel and slice the potatoes about 2 mm thick using a mandoline or a sharp knife (Like my Japanese one). Add slices directly to the warm mixture (do not rinse – the starch helps thicken the sauce).

• Step 5

  Bring to a gentle simmer, stirring now and then so the bottom doesn’t catch. As soon as it starts to bubble, reduce heat to low and simmer 8 minutes until just tender.

• Step 6

  Taste the liquid and adjust seasoning if needed. Using a slotted spoon, transfer half the potatoes into an about 8.5 by 12.5-inch (22 by 32-cm). baking dish, spreading flat. Scatter a few thyme leaves and a handful of cheese between layers. Add remaining potatoes, arrange the top layer neatly overlapping, and sprinkle a few more thyme leaves if desired.

• Step 7

  Pour remaining liquid over potatoes until just covered. Top with remaining cheese.

• Step 8

  Cover loosely with foil and bake for 40 minutes to allow the centre to cook through. Then remove the foil and continue baking uncovered for another 25–30 minutes, or until bubbling, deeply golden, and a knife slides through easily.

• Step 9

  Let rest for 60 minutes, covered with foil and a kitchen towel, so the cream can set and the layers hold together. The potatoes will remain hot.

Little Tips

If making ahead, bake until just set, cool, then reheat covered at 160°C for 25 minutes to serve perfectly creamy again.