Name: Cheesy Potato Gratin Recipe
Prep time: 20 min
Cook time: 1 h 30 min
Total time: 1 h 50 min
Cuisine: French
Ingredients: 3 ounces finely grated Gruyère or comté cheese; 2 ounces finely grated Parmigiano-Reggiano; 2 cups heavy cream; 2 medium cloves garlic, minced; 1 tablespoon fresh thyme leaves, roughly chopped; Kosher salt and black pepper, to taste; 4 to 4 1/2 pounds russet potatoes, peeled and sliced 1/8-inch thick on a mandoline slicer (7 to 8 medium potatoes); 2 tablespoons unsalted butter (for greasing the casserole dish)

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Introduction

Cheesy Potato Gratin is a comforting and elegant side dish featuring layers of thinly sliced russet potatoes baked in a rich, creamy mixture with Gruyère and Parmigiano-Reggiano cheeses. This recipe yields a golden, bubbly gratin with a crisp top that’s perfect for any special meal or cozy dinner.

An oval baking dish filled with a tightly arranged potato gratin showing thin slices of potatoes layered vertically in concentric rings around the dish’s edge, with a golden brown top layer of melted cheese and seasoning, the potato slices have a slightly crispy, browned texture on top, giving a warm and inviting look, all placed on a white marbled textured surface photo taken with an iphone --ar 4:5 --v 7

Ingredients

3 ounces finely grated Gruyère or comté cheese
2 ounces finely grated Parmigiano-Reggiano
2 cups heavy cream
2 medium cloves garlic, minced
1 tablespoon fresh thyme leaves, roughly chopped
Kosher salt and black pepper
4 to 4 1/2 pounds russet potatoes, peeled and sliced 1/8-inch thick on a mandoline slicer (7 to 8 medium)
2 tablespoons unsalted butter

Instructions

Step 1: Preheat the oven to 400°F (205°C) and adjust the oven rack to the middle position. In a large bowl, combine Gruyère and Parmigiano-Reggiano cheeses. Transfer one-third of this cheese mixture to a separate bowl and set aside for topping later.
Step 2: Add heavy cream, minced garlic, and chopped thyme to the remaining cheese mixture. Season generously with kosher salt and black pepper. Add the potato slices and gently toss with your hands, ensuring each slice is well coated and separated so the cream mixture distributes evenly.
Step 3: Butter a 2-quart casserole dish. Arrange the potato slices into neat stacks, placing them vertically and tightly packed in the dish, working from the perimeter inward. If needed, slice and coat additional potatoes to fill the dish completely.
Step 4: Pour the remaining cream and cheese mixture evenly over the potatoes until it reaches about halfway up the sides of the dish. You might not need all the liquid, so pour carefully.
Step 5: Cover the dish tightly with foil and bake for 30 minutes. Remove the foil and continue baking for another 30 minutes until the top turns pale golden brown.
Step 6: Sprinkle the reserved cheese evenly over the top and return the dish to the oven. Bake for about 30 more minutes until the top becomes deep golden brown and crisp. Let the gratin rest for a few minutes before serving.

Tips & Variations

Use a mandoline slicer for uniform potato slices which ensures even cooking and a smooth texture.
Swap fresh thyme for rosemary or sage for a different herb flavor.
For extra richness, drizzle a little melted butter over the top before the final bake.
Thinly sliced sweet potatoes can be used as a variation for a slightly sweeter gratin.

Storage

Store leftover gratin covered tightly in the refrigerator for up to 3 days. Reheat individual portions in the microwave or warm the whole dish covered with foil in a 350°F (175°C) oven until heated through, about 20 minutes. To refresh the crispy top, uncover during the last 5 minutes of reheating.

How to Serve

A round black cast iron pan holds a baked potato and sweet potato dish arranged in many thin, vertical layers that alternate between light yellow potato and orange sweet potato, standing upright in a swirling pattern from the center out to the edges. The top layers are golden-brown and slightly crispy with melted white cheese scattered on them, along with small bits of green herbs sprinkled throughout. The pan rests on a white marbled surface with a light gray cloth nearby. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I prepare the gratin ahead of time?

Yes, you can assemble the gratin up to a day in advance. Keep it covered in the refrigerator and bake it just before serving, adding a few extra minutes to the baking time if needed.

What type of potatoes work best?

Russet potatoes are ideal because they have a starchy texture that becomes tender and creamy when baked, holding the gratin’s structure well. Avoid waxy potatoes as they may result in a less tender dish.