Frequently asked questions

What is a gratin?

The French term gratin traditionally refers to any dish that is topped with cheese or a mix of breadcrumbs and butter, then prepared under a broiler so that the top becomes browned and crisp. (The term au gratin also refers to dishes that use that preparation). These creamy au gratin potatoes include neither cheese nor breadcrumbs, instead leaning on a thyme- and rosemary-infused heavy cream for its richness and browning.

Do I need to soak the potato and apple slices?

Soaking potato and apple slices in water can help prevent them from oxidizing and browning. In this recipe, because they’ll be baking and browning under a rich blanket of infused heavy cream, there’s no need to soak them first.

What kind of apples should I use in this gratin?

Apples that have a dense flesh and firm shape hold up well when cooked and are best for baking in this gratin. Granny Smith, Mutsu, and Gala are widely available baking apples. Heirloom varieties that hold their shape well include Cox’s Orange Pippin, Northern Spy, and Jonathan.

Notes from the Food & Wine Test Kitchen

Using a mandoline ensures thin, even slices, allowing the apples and potatoes to retain some of their integrity as they slowly bake in the creamy sauce. While a mandoline is ideal for uniformity, carefully slicing your produce by hand with a sharp knife can work just as well.

Fennel pollen, which has a citrus- and anise-like flavor and is harvested from fennel frond blossoms, can be found at most specialty grocery stores or online at bonafurtuna.com.

Suggested pairing

An orchard-fruity, full-bodied Rhône white, such as a Delas Frères Saint-Esprit Côtes-du-Rhône Blanc, complements these rich, creamy au gratin potatoes.

Ingredients

Softened unsalted butter, for greasing
1 3/4 cups heavy cream
2 1/2 teaspoons kosher salt, divided
1 1/8 teaspoons black pepper, divided
1/2 teaspoon fennel pollen (such as Bona Furtuna), plus more for garnish
3 medium garlic cloves, crushed
1 thyme sprig, plus fresh thyme leaves for garnish
1 rosemary sprig
3 (5- to 6-ounce) Yukon Gold potatoes, peeled and sliced crosswise into 1/8-inch-thick slices (about 2 1/2 cups)
3 large shallots, thinly sliced lengthwise (about 2 cups)
1 large Pink Lady apple (unpeeled), cored and sliced lengthwise into 1/8-inch-thick slices (about 2 cups)
1 large Granny Smith apple (unpeeled), cored and sliced lengthwise into 1/8-inch-thick slices (about 2 cups)

Directions

Preheat oven to 425°F with rack 7 to 8 inches from heat. Generously grease a broiler-safe 3- to 3 1/2-quart ceramic baking dish or gratin dish with butter.
Combine cream, 2 teaspoons salt, 1 teaspoon pepper, fennel pollen, garlic, thyme sprig, and rosemary sprig in a medium saucepan. Bring mixture to a simmer over medium, stirring occasionally. Remove from heat; cover and let stand 15 minutes. Remove and discard garlic and herb sprigs. Set aside.
Layer potato, shallot, and apple slices alternately in upright rows in prepared pan. Pour infused cream evenly over top; sprinkle with remaining 1/2 teaspoon salt and remaining 1/8 teaspoon pepper.
Bake gratin in preheated oven until cream bubbles and potatoes, shallots, and apples are tender but not mushy, about 40 minutes. Increase oven temperature to broil; broil until top is lightly browned, 1 to 2 minutes. Remove from oven; let stand 10 minutes. Garnish gratin with additional fennel pollen and thyme leaves. Serve hot.