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Walla Walla onion and pine mushroom fonduta recipe

Walla Walla Onion and Pine Mushroom Fonduta is a delightful vegetarian dish that showcases the natural sweetness of Walla Walla onions paired with earthy, tender pine mushrooms. This comforting fonduta is enriched with creamy double cream and aromatic thyme, creating a luscious, savoury experience that is perfect for sharing. The warmth of melted gruyère-style cheese and the crunch of day-old Arctic sourdough add layers of texture and flavour, making this dish a true indulgence for any occasion.

Ideal for a family gathering or a cosy evening in, this fonduta is not only satisfying but also a wonderful way to incorporate seasonal ingredients into your meals. Serve it as a dip alongside toasted sourdough or as a rich accompaniment to grilled vegetables, and enjoy the comforting embrace of this homemade treat that celebrates the best of vegetarian cooking.

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Ingredients for Walla Walla onion, pine mushroom fonduta

  • 4 whole sweet onions (Walla Walla, about 450 g each)

  • 120 g coarse salt, for roasting

  • 120 ml extra virgin olive oil

  • 240 g peeled, washed, thinly sliced pine mushrooms

  • 30 g plain flour

  • 480 ml vegetable stock

  • 120 ml double cream

  • reserved chopped innards from onions

  • 30 ml thyme leaves, chopped

  • fresh-ground black pepper

  • 120 g small torn pieces of day-old Arctic sourdough

  • 240 g grated gruyère-style cheese (we like Farm House Natural Cheeses Heidi)

  • 120 g grated gruyère-style cheese

  • Arctic sourdough

How to make Walla Walla onion, pine mushroom fonduta

  1. Preheat the oven to 230°C (fan) or 240°C (conventional).

  2. Trim the tops off the onions, removing about 2.5 cm, then replace the tops.

  3. Create a bed of coarse salt in a small roasting pan. Place the onions on the salt and roast for 45–60 minutes, until soft throughout.

  4. Once cool enough to handle, carefully scoop out the insides of the onions, leaving the outer two layers intact. Avoid scraping out the base to prevent the fonduta from leaking. Finely chop half of the onion innards for the filling and set aside.

  5. In a medium frying pan, heat the olive oil and add the sliced pine mushrooms. Sweat for 5 minutes until softened.

  6. Stir in the flour and sauté for an additional minute.

  7. Add the vegetable stock and single cream, then bring to a simmer.

  8. Stir in the reserved chopped onion, thyme, and season with salt and pepper to taste.

  9. Incorporate the day-old sourdough bread pieces and cook for 5 minutes to meld the flavours.

  10. Add the grated Gruyère, stirring until melted, then remove from heat.

  11. Preheat the oven to 230°C (fan) or 240°C (conventional).

  12. Place the roasted onions in a roasting pan and fill with the hot pine mushroom fonduta (any extra can be served on the side).

  13. Top with the remaining grated Gruyère and roast for 10 minutes, until bubbly.

  14. Serve with plenty of Arctic Sourdough and any extra fonduta that did not fit in the onions.

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.

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Article history

The information on this page is peer reviewed by qualified clinicians.

  • 30 Oct 2025 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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