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Apple, Potato, and Onion Gratin

This apple, potato and onion gratin is a sophisticated vegetarian side dish that offers a refreshing departure from traditional heavy bakes. By omitting the usual cream and cheese, the natural sweetness of the tart apples and caramelised onions can truly shine, beautifully balanced by the earthy scent of fresh thyme. It is an elegant addition to any Sunday roast or a festive spread, providing a lighter but deeply satisfying alternative to a classic dauphinoise.

Highlighting the best of seasonal produce, this recipe uses a simple emulsion of butter, white wine and sugar to create a rich, syrupy glaze that coats κάθε slice of potato. Whether you are serving it for a family gathering or a dinner party, this versatile dish is remarkably easy to prepare and can even be made ahead of time, allowing you to focus on your guests while it fills the kitchen with a comforting, savoury aroma.

Continue reading below

Ingredients for Apple, Potato, and Onion Gratin

  • 12 tablespoons (1 1/2 sticks) butter, divided

  • 900g onions, sliced

  • 2 tablespoons (packed) chopped fresh thyme

  • 4 teaspoons fine sea salt, divided

  • 160ml water

  • 160ml dry white wine

  • 4 teaspoons sugar

  • 1.1kg Yukon Gold, yellow Finn, or German Butterball potatoes, peeled, cut into 1/4-inch-thick rounds

  • 900g tart apples (such as Granny Smith, Pippin, or Pink Lady), peeled, halved, cored, cut into 1/4-inch-thick slices

How to make Apple, Potato, and Onion Gratin

Preheat oven to 204°C. Butter 13x9x2-inch glass or ceramic baking dish. Melt 90ml butter in large nonstick skillet over medium heat. Add onions, thyme, and 2 teaspoons salt; sauté until onions are translucent, about 10 minutes. Increase heat to medium-high; sauté until onions are tender and begin to colour, about 8 minutes longer. Remove from heat. Add remaining 6 tablespoons butter, 160ml water, wine, and sugar to skillet; stir and swirl skillet to combine. Bring to boil. Cool onion mixture to lukewarm.

Combine potatoes, apples, remaining 2 teaspoons salt, and onion mixture in large bowl; toss gently to blend. Transfer to prepared baking dish, spreading evenly. Cover dish with parchment paper, then cover with foil, shiny side down. Bake gratin until potatoes are tender, about 55 minutes. Uncover and bake until top browns and juices bubble thickly, about 20 minutes longer. (Can be made 6 hours ahead. Let stand uncovered at room temperature. Rewarm, loosely covered with foil, in 149°C oven for 20 minutes.) Let gratin stand 15 minutes before serving.

This gratin is unusual for having no cream or cheese — letting the lovely seasonal flavours of the produce shine through.

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.

  • 17 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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