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Potato Fennel Gratin

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

Meets Patient’s editorial guidelines

This elegant potato fennel gratin is a sophisticated twist on a classic side dish, combining the earthy comfort of potatoes with the delicate, aniseed notes of fresh fennel. By slicing the vegetables finely and slow-baking them under foil, the flavours meld beautifully to create a tender, savoury interior. A final topping of nutty Gruyère cheese provides a beautifully crisp, golden crust that contrasts perfectly with the soft layers beneath.

As a versatile vegetarian dish, this gratin is an excellent accompaniment to a Sunday roast or a simple grilled main. It is particularly well-suited for entertaining, as it uses humble ingredients to produce a result that feels truly indulgent. Serve it hot from the oven with a scattering of fresh green fronds for a light, aromatic finish that will impress any guest.

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Ingredients for Potato Fennel Gratin

  • 1 (450g ) fennel bulb with fronds

  • 900g boiling potatoes

  • 4 tablespoons (60g ) unsalted butter, melted

  • 230g coarsely grated Gruyère cheese (90g)

  • a handheld adjustable-blade slicer

How to make Potato Fennel Gratin

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Preheat oven to 232°C with rack in lower third of oven. Butter a 2-quart shallow flameproof gratin pan or baking dish (not glass.)

Cut fronds from fennel and chop enough to measure 1 tablespoon . Set aside. Cut off and discard stalks. Quarter fennel lengthwise and cut very thinly with slicer into a large bowl.

Peel potatoes and cut very thinly with slicer into bowl. Add butter with 3/4 teaspoons salt and 1/4 teaspoons pepper and toss to coat.

Transfer vegetables to gratin dish, spreading them out in an even layer, and cover tightly with foil.

Bake 30 minutes, then reduce oven to 177°C and continue to bake until vegetables are tender, 20 to 25 minutes more.

Remove from oven and remove foil, then sprinkle gratin evenly with cheese.

Preheat grill and grill gratin 4 to 5 inches from heat just until cheese is lightly golden 4 to 5 minutes.

Let gratin stand 5 minutes before serving.

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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