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Classic Potato Gratin

Peer reviewed by UK recipe editorsAuthored by UK recipe editorsOriginally published 28 Jan 2026

Meets Patient’s editorial guidelines

This classic potato gratin is the ultimate comforting side dish, featuring thinly sliced potatoes bathed in a rich, garlic-infused cream sauce. By blending the aromatics directly into the double cream, every bite is infused with a deep, savoury flavour that perfectly complements the earthy russet potatoes. The addition of nutty Gruyère and sharp Parmesan creates a beautifully burnished, bubbling crust that provides a sophisticated finish to this vegetarian favourite.

Ideal for a Sunday roast or a festive dinner party, this versatile dish can be prepared a day in advance to save time in the kitchen. Simply bake the potatoes through, then chill and bring back to room temperature before adding the cheese and grilling until crisp. Serving this homemade gratin alongside roasted vegetables or a crisp green salad makes for an elegant, heart-warming meal.

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Ingredients for Classic Potato Gratin

  • 5 garlic cloves, divided

  • 1 tablespoon unsalted butter, room temperature

  • 2 medium shallots, quartered through root ends

  • 600ml double cream

  • 1 tablespoon kosher salt

  • 1 teaspoon freshly ground black pepper

  • 1 tablespoon thyme leaves, plus more

  • 1.8kg russet potatoes, scrubbed, very thinly sliced on a mandoline

  • 90g Gruyere, finely grated

  • 30g Parmesan, finely grated

How to make Classic Potato Gratin

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Preheat oven to 163°C. Cut 1 garlic clove in half and rub the inside of a 3-qt. shallow baking dish with cut sides. Smear butter all over inside of dish. Bring shallots, cream, salt, pepper, 1 tablespoon thyme, and remaining 4 garlic cloves to a simmer in a small saucepan over low heat; cook until shallots and garlic are very soft, 15–20 minutes. Let cool slightly. Transfer to a blender; blend until smooth.

Arrange potato slices in prepared dish, fanning out a handful at a time and placing in dish at an angle (this ensures every scoop will have tender potatoes from the bottom and crisp edges from the top). Shingle as you work until bottom of dish is covered. Tuck smaller slices into any gaps to fill. Pour cream mixture over potatoes and cover dish tightly with foil. Bake potatoes until tender and creamy, 60–75 minutes. Let cool.

Place rack in highest position; heat grill. Remove foil and top potatoes with Gruyere and Parmesan. Grill until cheese is bubbling and top of gratin is golden brown, 5–10 minutes. Serve topped with more thyme leaves.

Gratin can be baked 1 day ahead. Cover and chill. Bring to room temperature before grilling.

Disclaimer

While every effort has been made to ensure the information is accurate and up to date, individual needs may vary and dietary requirements can differ based on personal health conditions. Always check food labels and allergen information before preparing or consuming any recipe. If you have specific health concerns, allergies, intolerances, or are following a medically prescribed diet, seek advice from your GP, pharmacist, or a registered dietitian before making significant changes to your diet or lifestyle.

Article history

The information on this page is peer reviewed by qualified clinicians.

  • 28 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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