Caramelised Onion Tart With Blue Cheese

December 20, 2019

Nothing prepares you more for busy days, uninspired shopping trips or last minute guests than a stack of easy and trusty recipes to fall back on! Well, this recipe can be added to that stack – this caramelised onion tart is easy to throw together, hearty & delicious and it looks pretty good too!

As you might have guessed, onions are the star of the show in this recipe. They are super flavoursome and such a comforting staple to use during wintertime. The onions are caramelised in a skillet first and drizzled with balsamic vinegar for that extra depth of flavour and tanginess. They become even more yummy while baking in the oven until soft, sweet and delicious.

Onions and thyme are a match made in heaven – as are blue cheese and balsamic vinegar! This recipe combines those all, cased in a yummy flaky pastry. Use fresh thyme sprigs for this recipe, as dried thyme won’t give you the same flavour results. For the blue cheese, pick a slightly crumbly and creamy cheese that you love to eat; you can opt for a milder or more strong version based on your own preferences.

This tart is easy to whip up with ingredients you might have on hand already! It’s perfect to throw together for a last minute lunch with friends or a late night snack. Eat it for dinner with steamed vegetables in winter or a big side salad in summer. You can easily adapt it to your own preferences too – see the notes under the recipe for a vegan option or blue cheese replacements.

Looking for more hearty recipes? Try out this Warming Curried Lentil Soup or these Simple Roasted Winter Vegetables!

Are you ready to get cooking? Let’s make a delicious onion tart!

Recipe: Caramelised Onion Tart With Blue Cheese

Time: 40 min Servings: 4

These ingredients are based on a tart case of 14 x 4 inches (35x11cm). You can easily adapt the ingredients to another size by placing the raw onion slices in the case – you need enough to fit them in snuggly. You could also use a square or round case.


  • 4 big yellow onions
  • knob of butter or olive oil
  • about 4 fresh thyme sprigs
  • 2 tbsp balsamic vinegar + more for serving
  • 1 tbsp honey
  • 1/4 C (60ml) water
  • salt & pepper
  • a sheet of puff pastry (enough to line your case)
  • 3,5 oz (100 gr) Blue Cheese


  1. Preheat your oven to 390°F/200°C.
  2. Slice the end of the onions and peel their skin off. Slice the onions in about 3 or 4 rings (depending on the size of your onions), you want about 0.5 inch (1,5 cm) thickness.
  3. Heat a skillet on the stove and add the butter or oil, the fresh thyme sprigs and the onion slices. Once the onions start to brown, add 2tbsp of balsamic vinegar, the honey and the water and turn down the heat. Cover and let it simmer for about 10 min until the onions are soft. Season with salt & pepper. If needed, let any liquid evaporate until it’s sticky.
  4. In the mean time, grease and line a tart case with puff pastry.
  5. Once the onions are soft, place them into the tart case – fit them in as snuggly as you can without squashing them. You can cut the rings in half to fill up any empty spots. Brush the leftover syrupy juices from the pan over the rings.
  6. Bake the tart in the oven for about 20 min or until the pastry is cooked golden brown.
  7. Crumble the blue cheese over the tart and add a drizzle of balsamic vinegar. Serve immediately!


This recipe is easily adaptable:

Make it vegan by opting for vegan puff pastry and replacing the blue cheese for walnuts and rocket leaves.

If you’re not a fan of blue cheese you can easily replace it with soft goats cheese or a lovely aged cheddar or parmigiano.

As always, let me know if you try it and leave any comments and questions down below! Also, don’t forget to subscribe to the blog to stay updated on any new content (and I’ve got loads of good stuff coming your way in the new year!).

Eve x

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