4 garlic cloves, 1 clove cut in half lengthwise, remaining cloves minced
1 tablespoon unsalted butter, softened
1 cut shredded Gruyere or Swiss cheese
1 cup coarsely grated Parmesan cheese
1 1/2 cups heavy cream
1 1/2 cups low-sodium chicken broth
2 teaspoons chopped fresh thyme
1/8 teaspoon nutmeg
3/4 teaspoon salt
1/8 teaspoon pepper
2 1/2 pounds russet potatoes (4 to 5 medium), peeled and sliced 1/8 inch thick
4-5 slices hearty white sandwich bread, crusts removed and torn into pieces (about 4 cups)
Adjust oven rack to middle position and heat oven to 350° F. Use cut side of halved garlic to rub sides and bottom of 2-quart shallow baking or gratin dish. Allow garlic in dish to dry briefly, about 2 minutes, then coat dish with softened butter. Combine cheeses in small bowl.
Bring minced garlic, cream, broth, thyme, nutmeg, salt and pepper to boil in large saucepan over medium-high heat. Reduce heat to medium-low and simmer until liquid is reduced to 2 1/2 cups, about 5 minutes. Remove from heat and gently stir in potatoes.
Spoon half of potato mixture into prepared dish. Sprinkle with half of cheese, add remaining potato mixture, and press with spatula to compact. Press bread pieces into casserole. Bake 40 minutes. Sprinkle remaining cheese on top and continue baking until golden and bubbling, 25 to 30 minutes. Remove from oven and let rest 20 minutes before serving.
Make Ahead : This casserole can be assembled (leave off the bread) and refrigerated up to 24 hours. When ready to bake, add bread topping and bake according to the recipe. If you are cooking for a crowd, double the ingredients and use two baking dishes of similar size.
Recipe courtesy of Mary Ann Montgomery, Laura’s great aunt.