Caramelised onion tart

Caramelised onion tart

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(10 ratings)

Ready in 1¼ to 1½ hrs


Serves 4
This tart is luscious and tasty, there’s very little shopping involved and everyone seems to love it

Nutrition and extra info

  • Freezable
  • Vegetarian

Nutrition: per serving

  • kcal730
  • fat49g
  • saturates21g
  • carbs55g
  • sugars0g
  • fibre4g
  • protein21g
  • salt0.92g
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  • 375g pack ready-rolled shortcrust pastry
  • 500g onions, finely sliced



    Onions are endlessly versatile and an essential ingredient in countless recipes. Native to Asia…

  • 3 tbsp olive oil
    olive oil

    Olive oil

    ol-iv oyl

    Probably the most widely-used oil in cooking, olive oil is pressed from fresh olives. It's…

  • few sprigs thyme, leaves only


    This popular herb grows in Europe, especially the Mediterranean, and is a member of the mint…

  • 3 eggs



    The ultimate convenience food, eggs are powerhouses of nutrition packed with protein and a…

  • 300ml milk



    One of the most widely used ingredients, milk is often referred to as a 'complete' food…

  • 100g ready grated emmental


  1. Heat oven to 190C/fan 170C/gas 5. Slide a baking sheet in to heat. Roll the pastry out enough to line a deep 20cm flan tin or a shallow 23cm one. Chill for 10 mins.

  2. Put a few balls of crumpled foil in the base of the pastry case and bake on the baking sheet for 10 mins. Remove the foil and bake for 5 mins more, until light golden.

  3. Meanwhile, cook the onions in the oil until starting to soften, then add thyme, pepper, and salt if you want to. Cook slowly for about 15 mins until the onions are soft and tinged brown.

  4. Beat the eggs, beat in the milk and half the cheese and some pepper. Spread the onions over the flan case and pour in the egg mix. Sprinkle the remaining cheese on top and bake the tart on the baking sheet for 30-40 mins until the filling is firm and golden, and the pastry crisp. Serve warm or cold.

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Comments, questions and tips

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28th May, 2020
Tasted fine but the amounts are wildly off. Used the exact amounts of every ingredient and the correct size tin suggested. The amount of egg/milk mixture is too much to fill the flan tin even if there was no pastry/onion in it. If you’re doing this I’d recommend using 2/3 or maybe even half the amount of milk/eggs
26th Aug, 2017
Habdabs, the courgettes need to be salted as they are a water vegetable. I found this out the hard way when I couldn't get leeks for my usual leek tart recipe. The courgettes turned it to mush.
27th Sep, 2015
It's certainly quick and easy but I found that the 300ml milk / 3 eggs combo gave far too much liquid and flooded the tart. I like to pack my tarts with veg so had added some courgettes with the onions and found 200/2 works better.
Gluten Free Spirit's picture
Gluten Free Spirit
28th Jul, 2014
I made this for a buffet and it was lovely. A couple of alterations: used ready made gluten free pastry to make it suitable for coeliacs; changed the emmental to a strong cheddar for zing; added a dash of sherry vinegar and a sprinkle of sugar to the onions to really caramelize them. It was gorgeous and got plenty of appreciative comments.
11th Aug, 2011
how very easy and lovely tasting xx a quick recipe
19th Apr, 2009
I added Balsamic vingear and garlic and a variety of cheese's to this recipe and it was lovely!
9th Sep, 2008
This is a really tasty dish, but I think when I make it again I would add more onion and change the cheese.
14th Aug, 2008
I made this with high hopes but I'm afraid that it was really disappointing.
29th Jul, 2008
I don't think I've made a quiche or tart like this since school, but so tempted by how it looked in the mag. It was so easy, and it tasted fantastic, my husband loved it. I made one a couple of nights ago using Gruyere as I didn't have any Emmental, thinking it would last two nights! no chance - all gone in one go! Looks like I'll have to make another tonight - will try Emmental this time
29th May, 2008
Really thought this would taste better than it did.


17th Nov, 2014
The recipe states that it is freezable. At what point can i freeze it and how long can it be frozen for? Do i need to cook from frozen or simply defrost and serve?
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