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Roasted Onions With Vinegar

Peer reviewed by UK recipe editorsAuthored by UK recipe editorsOriginally published 16 Jan 2026

Meets Patient’s editorial guidelines

This simple yet sophisticated side dish celebrates the humble onion, transforming it into something truly special through the power of slow roasting. By cooking the onions in their skins, the natural sugars caramelise beautifully, resulting in a combination of jammy, soft centres and slightly firm outer petals. A final toss in sharp red wine vinegar cuts through the richness, creating a balanced savoury flavour that works well throughout the year.

As a versatile low-fat option, these roasted onions are an excellent accompaniment to grilled meats, roasted chicken, or even served as part of a vegetarian mezze platter. Using a mix of small and medium varieties adds visual interest and a range of textures to the plate. It is a cost-effective, healthy way to add depth to any midweek dinner or Sunday roast.

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Ingredients for Roasted Onions With Vinegar

  • 1.8kg mixed small and medium onions (such as Vidalia or yellow)

  • 2 tablespoons olive oil

  • 2 tablespoons red wine vinegar

  • Kosher salt, freshly ground pepper

How to make Roasted Onions With Vinegar

Preheat oven to 204°C. Arrange onions on a rimmed baking sheet and roast, shaking baking sheet halfway through, until the innermost layers of largest onions are just tender (some of the onions will be jammy and others will have some bite to them), 30–40 minutes. If you have one, a cake tester is a great tool to check doneness.

Transfer onions to a clean surface and let cool slightly. Halve through root ends and remove papery layers. Separate layers into individual petals and transfer to a platter or a large bowl. Drizzle with oil and vinegar and toss gently to coat; season with salt and pepper.

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.

  • 16 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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