• Make-Ahead

Ingredients

1. 3 cups heavy cream
2. 15 garlic cloves, smashed
3. 4 large thyme sprigs
4. 2 bay leaves
5. 1 teaspoon freshly grated nutmeg
6. 1/2 teaspoon black peppercorns
7. Salt and freshly ground pepper
8. 4 pounds baking potatoes, peeled and sliced 1/8 inch thick

Directions

1. In a medium saucepan, combine the cream, garlic, thyme, bay leaves, nutmeg and peppercorns and bring to a boil. Remove from the heat, cover and let stand for 1 hour. Strain the cream. Season generously with salt and pepper. 
2. Preheat the oven to 375°. Butter a 3-inch deep 3-quart oval baking dish. Spread one-fourth of the potatoes in the dish. Season with salt and pepper and drizzle with one-fourth of the cream. Repeat the layering twice, seasoning as you go. Arrange the last layer in concentric circles. Drizzle with the remaining cream. Press the potatoes down to submerge in the cream. Press a sheet of lightly buttered parchment paper onto the potatoes. Cover the dish with foil. 
3. Bake for 45 minutes, or until the potatoes are barely tender when pierced with a knife. Remove the foil and parchment and bake for 40 minutes longer, or until the potatoes are tender, the cream is absorbed and the top is golden. Let stand for 10 minutes; serve.

Make Ahead

The gratin can be made early in the day; reheat in a 325° oven.

Notes

Gratins are wonderfully simple side dishes that welcome experimentation. For example, play around with the infusion in Step 1. Instead of (or in addition to) thyme, try rosemary or sage or add the white part of a roughly chopped leek to the mix.

In addition to the potatoes here, you could add some peeled, thinly sliced turnips or sweet potatoes for some great color. For a garnish, try some snipped chives.