Ingredients

• • 4 tablespoons (1/2 stick) butter: 2 tablespoons at room temperature, 2 tablespoons cut in 8 pieces
• • 4 large cloves garlic, peeled
• • 2 cups milk
• • 2 cups whipping cream
• • 1 1/2 to 2 teaspoons kosher salt, plus more as needed
• • 4 large russet (baking) potatoes (about 3 pounds)
• • Freshly ground pepper
• • 3 cups of shredded Gruyere cheese (imported preferred)

Instructions

1. Preheat the oven to 350˚F. Butter a 2-quart casserole dish with the 2 tablespoons room-temperature butter and rub with 1 of the garlic cloves. Discard the clove.
2. Combine the milk and cream in a large saucepan. Add the salt and taste to be sure it tastes salty. Add the remaining 3 garlic cloves and bring to a boil, then reduce the heat and simmer 5 minutes, being careful not to let the mixture boil over.
3. Meanwhile, peel and rinse the potatoes. Pat dry. Using a mandoline, slicer, or knife, cut into 1/8-inch-thick slices. For an extra twist, use a crinkle cutter for ruffled potatoes. Making a circular pattern, overlap the slices to cover the bottom of the casserole.
4. Top with 1/4 cup of the milk mixture and a few grinds of pepper, a sprinkle of salt, and 3/4 cup of the cheese. Repeat this layering, reserving 1/2 cup of the cheese, until you have only 1/2 inch left at the top of the dish.
5. Use a slotted spoon to remove the garlic, and pour the remaining milk mixture through a strainer into the casserole until the potatoes are covered. You might not use all the milk. Do not overfill the casserole dish- maintain a 1/2 inch of space at the top of the dish once the milk sinks in. Top with the reserved cheese and scatter the butter pieces over the top.
6. Line a baking sheet with foil and place the casserole dish on the sheet. Bake 30 to 45 minutes, until the top is bubbling, the cheese is brown, and a knife easily pierces the potatoes. Let rest 10 to 12 minutes, then serve.