For steeping cream
- 2 ¼ cups half-and-half
- 2 medium cloves garlic (8g), smashed
- 2 small shallots (110g total), quartered
- 1/8 teaspoon freshly grated nutmeg
- 6 sprigs fresh thyme
- 2 teaspoons (6g) whole black peppercorns
- 1 ¼ teaspoons table salt
In a small saucepan, combine cream, milk, garlic, shallots, nutmeg, thyme, peppercorns, and salt. Bring to a boil, then remove from heat, cover, and let steep for 1 hour.
- 2 pounds all-purpose potatoes, peeled and sliced 1/8-inch thick or less
- Adjust oven rack to center position and heat oven to 350 degrees. Rub bottom and sides of 5- to 6-cup gratin dish or shallow baking dish with a garlic clove. Once garlic in dish has dried, about 2 minutes, spread dish with half the butter.
- Bring steeped half-and-half and potatoes to boil in medium saucepan over medium-high heat, stirring occasionally with wooden spoon (liquid will just barely cover potatoes). Reduce heat and simmer until liquid thickens, about 2 minutes.
- Pour potato mixture into prepared dish; shake dish or use fork to distribute potatoes evenly. Gently press down potatoes until submerged in liquid; dot with remaining butter.
- Bake until top is golden brown (basting once or twice during first 45 minutes) about 1 hour 15 minutes.
- For a more pronounced crust, sprinkle three tablespoons of heavy cream or grated Gruyère cheese on top of the potatoes after forty-five minutes of baking. Let rest 5 minutes and serve.