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Fennel Gratin with Walnut-Thyme Breadcrumbs

This elegant fennel gratin with walnut-thyme breadcrumbs is a sophisticated vegetarian side dish that celebrates the delicate, aniseed flavour of fresh fennel. Slowly baked in double cream and butter, the fennel slices soften beautifully, absorbing the savoury notes of the onion and herbs. It is a wonderful alternative to traditional potato-based bakes, offering a lighter yet equally indulgent texture that pairs perfectly with roast dinners or a simple green salad.

The standout feature of this dish is the golden topping, which combines very coarse fresh breadcrumbs with earthy walnuts for a satisfying crunch. The addition of salty Parmesan and aromatic thyme provides a complex depth of flavour that cuts through the richness of the cream. Whether you are looking for a show-stopping vegetable dish for a festive menu or a comforting weekend treat, this homemade gratin is a reliable and delicious choice.

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Ingredients for Fennel Gratin with Walnut-Thyme Breadcrumbs

  • 900g fennel bulbs (about 4 small), thinly sliced lengthwise

  • 1 small onion, thinly sliced

  • 240ml double cream

  • 4 tablespoons unsalted butter, cut into small pieces

  • 2 tablespoons thyme leaves, divided

  • Kosher salt, freshly ground pepper

  • 170g very coarse fresh breadcrumbs

  • 240ml walnuts, coarsely chopped

  • 2 tablespoons olive oil

  • 30g finely grated Parmesan (about 240ml )

Place rack in upper third of oven; preheat to 204°C. Place fennel, onion, cream, butter, and 1 tablespoon thyme in a large bowl. Season with salt and pepper and toss to combine. Transfer to an 8x8" baking dish; bake until fennel is crisp-tender and cream is reduced by half, 30–35 minutes.

While fennel is baking, combine breadcrumbs, walnuts, and oil in a medium bowl. Season with salt and pepper and toss until bread is evenly saturated and walnuts are coated. Add Parmesan and remaining 1 tablespoon thyme and toss again to combine.

Scatter breadcrumb mixture evenly over gratin and bake until breadcrumbs and walnuts are deep golden brown and fennel is tender, 12–15 minutes. Let cool slightly 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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