Creamy Celeriac and Potato Gratin with a Toasted Hazelnut Crust

Discover the secret to the most luxurious winter side dish imaginable. By pairing the earthy, subtle sweetness of celeriac with the buttery richness of Yukon Gold potatoes, you create a complex flavor profile that is elevated by a fragrant garlic-thyme cream infusion and a decadent, crunchy hazelnut-Gruyère topping that promises to impress at any dinner table.

This gratin serves as the perfect centerpiece for a sophisticated meal or a cozy evening at home. The delicate process of slicing root vegetables into paper-thin discs allows them to absorb the herb-infused cream, resulting in a texture that is simultaneously meltingly tender and structurally sound.

The final addition of crushed roasted hazelnuts provides a delightful textural contrast to the soft, creamy interior, making every forkful a memorable experience of classic French culinary techniques adapted for the home kitchen.

Ingredients

Why this recipe works

The method of simmering the cream with garlic, thyme, and bay leaf before baking is essential for building a deep, aromatic base that penetrates the vegetables.

This infusion ensures that the flavor is not merely resting on the surface but is distributed throughout the entire dish, creating a cohesive and harmonious taste profile that defines a high-quality gratin.

Using a mandoline to maintain a consistent 2mm thickness for the celeriac and potatoes is the key to success. This uniformity ensures that every slice reaches the same level of tenderness simultaneously, preventing uneven cooking and ensuring the final dish has a beautiful, professional appearance when served in layers on the dinner plate.

Notes and substitutions

For the cheese selection, cave-aged Gruyère is highly recommended for its nutty and slightly salty complexity, which pairs perfectly with the roasted hazelnuts.

If unavailable, use a high-quality Swiss cheese or even a blend of Comté and Emmental. Ensure the hazelnuts are freshly roasted to maximize their aromatic oils, which are critical for the signature crunch of this gratin.

Regarding equipment, a mandoline is the most reliable tool for achieving the thin, precise slices required for this dish.

If you do not own one, a very sharp chef knife and steady hands will suffice, though it may take extra time to achieve the desired consistency. A ceramic baking dish is ideal as it retains heat exceptionally well, keeping the gratin warm throughout the meal.

• Yukon Gold potatoes: Russet potatoes or any waxy potato variety that holds its shape well after baking.
• Gruyère: Emmental, Comté, or a sharp white cheddar cheese for a different flavor profile.
• Roasted hazelnuts: Toasted walnuts or sliced almonds can provide a similar nutty crunch.

Equipment

• Mandoline slicer
• Large saucepan
• 9x13 inch ceramic baking dish
• Chef knife
• Grater