Step 1

Preheat your oven to 375°F (190°C).

Step 2

Begin by roasting the garlic. Cut the top off the head of garlic to expose the cloves. Place the garlic head on a piece of aluminium foil, drizzle with olive oil and season with a pinch of salt. Wrap the foil around the garlic and roast it in the preheated oven for about 30 minutes, or until the cloves are soft and golden. Once roasted, allow the garlic to cool slightly before handling.

Step 3

While the garlic is roasting, grease a 9x13-inch (23x33 cm) baking dish and set aside.

Step 4

Then peel and thinly slice the potatoes. I recommend using a mandoline slicer for even slices.

Step 5

Take a stack of potatoes and arrange them upright in layers within the dish (check the video below). Continue layering until all potatoes are used.

Step 6

In a saucepan, combine heavy/double cream, milk, butter, half of the grated parmesan cheese, thyme, nutmeg, pinch of salt and pepper. Heat over medium heat until butter is melted and the ingredients are well combined. Do not let it boil.

Step 7

Once garlic is roasted, squeeze the garlic cloves out of their skins and mash them into a paste. Stir the roasted garlic paste into the cream mixture until well combined.

Step 8

Pour the creamy mixture over the potatoes in the baking dish, ensuring they are evenly coated. Cover the dish tightly with kitchen foil.

Step 9

Bake the potatoes au gratin in the preheated oven for 40 minutes.

Step 10

Remove the foil and top the potatoes with the shredded Gruyere or mozzarella cheese and the remaining 1/4 cup of grated parmesan cheese.

Step 11

Return the dish to the oven, uncovered, and bake for an additional 30 minutes, or until the cheese is bubbly and golden brown and potatoes are fork tender.

Step 12

Once done, remove the potato au gratin from the oven and let it cool for a few minutes before serving.

Step 13

Garnish with fresh chives and enjoy!