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Thyme and leek (or onion) tart recipe

October 11, 2021

Leek and thyme tartHaving a store cupboard tart recipe is deeply rewarding. Whipping one up for supper, lunch or last minute gatherings with little effort is so much better than grabbing something from supermarket shelves. Even delicatessen quiches pall in the fridge and are costly if buying more than one slice. I love to have a few recipes that I can turn to with without a second thought.

The pages of Herb/a cook’s companion are already well-thumbed and I’ve cooked the Lemon Thyme and Leek Tart several times as it’s deliciously simple.

The fiddly part of savoury tarts is baking the crust blind (lining a tart tin with pastry, putting in baking paper and beans, cooking for 15-20 minutes) before adding the filling. My usual standby, mascarpone and bacon, dispenses with this stage without suffering from the now ubiquitous condition of ‘soggy bottom’; fearing having a layer of rather stodgy, almost uncooked pastry underneath your eggy topping.  This tart goes a step further in simplicity as you don’t even have to line a tin (meaning the dreaded shrinkage is not a problem either). You just fold the edges in for a rather lovely rustic look. If cooking competition perfection is your aim then this might not be for you – or you could make it in a tart tin.

Herb cookbook and thyme and leek tart

My herb patch doesn’t include lemon thyme this year. Recipe writer and author Mark Diacono recommends it but also describes the difference that each variety offers in the recipe intro.

Lemon thyme makes the sunniest, orange thyme is altogether more resinous and autumnal, and common thyme gives a tart you could eat for breakfast, lunch and tea and not tire of it.

Even if I’ve had to pull on my wellies and raincoat, I’ve found picking my own leaves fresh from the garden a simple pleasure. The scent of them is deep and sombre. Thyme is a woody herb and withstands the obstacles of the supermarket supply chain pretty well. I’ve found it pretty easy to grow, both in Dubai and the U.K. (Herb has helpful instructions for this too).  A pot on your windowsill is a happy medium.

Here’s Mark’s recipe with a few notes from me. Like all good recipes, it’s started to evolve to my kitchen and way of cooking.


Uncooked onion and thyme tart

Thyme and Leek Tart

  • Servings: 4
  • Difficulty: simple
  • Print

A really simple to make tart that can be tweaked. I made it with common thyme, but lemon thyme and orange thyme all give different characters.

You can replace the leeks with onion, cooked in the butter slowly until they are sweet and melting. This amount of flour makes a generous amount of pastry. Don’t roll out too big a round or the filling won’t be very deep. Make cheese straws with any leftover bits. I only had dried bay leaves but use fresh ones if you have them.


For the pastry

  • 250g (9oz) plain flour, plus a little more for rolling
  • pinch of salt
  • 150g (5oz) unsalted butter, cubed
  • 1 medium egg, beaten
  • 1 teaspoon picked thyme leaves


For the filling

  • 30g (1oz) unsalted butter
  • 500g (1lb 2oz) leeks, white part only, thinly sliced or 500g onions (about 2 large) thinly sliced
  • 3 bay leaves
  • 2 medium eggs
  • 150g (5oz) sour cream or crème fraîche
  • 1 tablespoon picked thyme leaves
  • 1/4 whole nutmeg, or to taste, grated
  • freshly grated nutmeg (generous 1/2 teaspoon)
  • 20g (1/4oz) Parmesan or Cheddar, grated
  • sea salt and freshly ground black pepper


  1. For the pastry, put the flour, slat and butter into a food processor and pulse until the mixture resembles fine breadcrumbs. Add the thyme and pulse very briefly to combine. Add the egg and pulse until the mixture just comes together. (Alternatively, mix the butter into the flour and salt in a bowl using your fingertips until it resembles breadcrumbs, stir in the thyme, then add the egg and mix to form a dough.) Bring the dough together with your hands and shape into a round. Wrap the pastry in cling film (or greaseproof paper) and rest in the fridge for 30 minutes.
  2. Preheat the oven to 200C/400F/gas mark 6.
  3. Melt the butter in a pan over a low-medium heat, add the leeks and bay leaves and cook until really soft and sweet – about 15 minutes for leeks, 30 minutes for onions.
  4. Beat the eggs in a bowl, then scoop out a couple of tablespoons of beaten egg to glaze later. Add the sour cream, thyme leaves and nutmeg to the bowl. Stir in the leeks or onions and season to taste.
  5. Remove the pastry from the fridge and roll out to a circle about 3mm (1/4in) thick, leaving no gaps or holes. Place a sheet of baking paper on a baking sheet, and put the circle of pastry on to it. Spoon the creamy leeks (or onions) on top, spreading it out evenly and leaving a 1-2cm (1/4-1/2in) gap around the edge. Fold the edge of the pastry over to create a lip. Nudge the bay leaves to the top. Glaze all exposed pastry with the reserved egg and sprinkle the cheese over the top of the filling.
  6. Place the tart in the oven on a middle shelf and bake for 35-40 minutes until the pastry is crisp and pale golden and the tart filling is set. Remove from the oven and leave to cool for 5 or so minutes before cutting into wedges to serve. A swirl of herb oil or picada on top is optional.

onion and thyme tart with slices on plates

  1. October 11, 2021 3:45 pm

    Delicious! I rarely cook tarts/quiches living alone but they do make a lovely supper and then of course the leftovers are delicious too.

  2. October 11, 2021 9:00 pm

    I love these savory pies!

  3. Leslie permalink
    October 14, 2021 12:45 pm

    Are there two separate nutmeg ingredients, or just one that includes the grating of 1/4 nutmeg, and then measuring it out to the teaspoon???

  4. October 17, 2021 12:28 pm

    This sounds delicious. I have lots and lots of thyme, so I’m definitely going to make this recipe!

  5. March 27, 2022 11:08 am

    Lovely tart. Never tried with thyme and leek. Something different and delicious. Thanks for sharing.

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