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Root Vegetable Gratin

This seasonal root vegetable gratin is a sophisticated vegetarian side dish that brings a wonderful depth of flavour to any Sunday roast or festive spread. By combining earthy celeriac and parsnips with the subtle sweetness of sweet potatoes, this bake offers a more complex profile than a traditional potato dauphinoise. The vegetables are gently infused with garlic and nutmeg before being simmered in double cream until perfectly tender and golden.

Ideal for hosting, this comforting bake can be prepared ahead of time and finished under the grill just before serving to achieve that signature bubbling crust. While it is a natural partner for roasted meats, it also works beautifully as a standalone vegetarian main served with a crisp green salad. This recipe is a brilliant way to make the most of British winter produce during the colder months.

Continue reading below

Ingredients for Root Vegetable Gratin

  • 450g parsnips (about 4 medium)

  • 1 medium celery root (sometimes called celeriac

  • 350g total)

  • 450g sweet potatoes

  • 675g russet (baking) potatoes

  • 2 teaspoons salt

  • 1 teaspoon finely chopped garlic

  • 1/2 teaspoons black pepper

  • 1/4 teaspoons freshly grated nutmeg

  • 120ml reduced-sodium chicken broth

  • 425ml plus 2 tablespoons double cream

  • an adjustable-blade slicer

  • a 3-quart gratin or other shallow flameproof baking dish (not glass

  • 13 by 9 inches)

How to make Root Vegetable Gratin

Put oven rack in upper third of oven and preheat oven to 204°C.

Peel parsnips and cut crosswise into 3-inch lengths with a knife, then cut lengthwise around core into 1/8-inch-thick slices with slicer (discard core). Transfer to a large bowl.

Peel celery root and all potatoes (prepare russet potatoes last to avoid discoloration) and halve lengthwise, then cut crosswise into 1/8-inch-thick slices with slicer. Add to parsnips along with salt, garlic, pepper, nutmeg, broth, and 425ml cream, tossing to combine. Transfer to gratin dish, spreading evenly.

Cut out a piece of parchment or wax paper to fit just inside gratin dish, then butter 1 side of parchment. Cover vegetables directly with parchment, buttered side down, then put dish in a shallow baking pan (to catch any drips). Bake until gratin is bubbling all over and vegetables are tender when pierced with a knife, about 50 minutes. Discard parchment.

Just before serving, preheat grill. Drizzle top of gratin with remaining 2 tablespoons cream and grill 4 to 6 inches from heat until browned, 2 to 3 minutes.

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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