This Classic French Leek Tart with Gruyere Cheese and Onions makes the best lunch, entree or light main dish. Made with Shortcrust Pastry and a Leek, Onion and Gruyere Cheese Filling, it is a delicious vegetarian savoury tart the whole family will love!
Why we love this recipe
I simply ADORE a good savoury tart – and could eat it for any meal or course of the day! This Delicious Leek Recipe with Onions and Gruyere Cheese (“Flamiche aux Poireaux” in French) is a classic French/Belgian recipe that is great to serve at a party.
Leeks are such a great veggie to use in baking because it always brings SO much flavour to the dishes. I usually use some to make quiches like my Mushroom and Leek Quiche or with a Smoked Salmon and Leek Quiche, but it is equally delicious in the form of a savoury tart.
What is a “Flamiche aux Poireaux“
A ‘Flamiche aux Poireaux” is the traditional French name given to this savory tart. This dish originates from the North of France / Belgium. Often simply called a “Flamiche“, the full name of this dish includes “Poireaux” which simply means “Leeks” in French.
This savoury tart does resemble a Leek Quiche, but although this recipe contains Eggs and Cream (the basic Quiche Ingredients), the filling is mainly made from the vegetables and not a custard like a quiche.
You will find many different version of this tart, depending on the French and Belgian regions that make it. This recipe is made mainly from Leeks, with the addition of Gruyere Cheese and a small Brown Onion.
Savory Shortcrust Pastry
When it comes to a savoury tart pastry, I always just go back to basics with this simple shortcrust. It is basically the only one I use to make both savory tarts and quiche.
It is super flakey and buttery, and will perfectly hold a liquid filling like a quiche custard.
You will only need 4 ingredients to make this basic savory pastry (scroll down to recipe card below for all quantities):
- Plain / All-Purpose Flour: preferably sifted to avoid any lumps
- Salt: just a pinch is enough to flavour the pastry!
- Butter: unsalted and very cold, cut into small cubes
- Water – very cold
So basic… and simply full-proof!
You can also add other spices if you want. I often add Cumin Powder, Cumin Seeds, Dried Herbs or even Garlic Powder to my shortcrust pastries.
How to make Savory Shortcrust Pastry
Like always, I make my shortcrust pastry in the Food Processor as it is much quicker – and less messy. But you can absolutely make it by hands as well!
- Place the Flour and Salt in the bowl of your food processor.
- Cut the Butter into small cubes and add them to the flour. Blend until fully combined – you shouldn’t see any large lumps of butter anymore.
- Gradually add the cold water, a little bit at the time. Blend between each addition and stop as soon as the dough starts to come together. You may need a little less or more water.
- Transfer over a lightly floured sheet of baking paper. Assemble into a ball and slightly flatten it with your hands. Place a second sheet of paper over it and roll the pastry into the desire shape.
- Place in the fridge to rest for at least 30 minutes to 1 hour before lining in the tart pan. Rest again in the fridge for 1 hour, or in the freezer for 15 to 20 minutes before blind baking in an oven preheated on 180’C/350’F.
For more details on how to make this savoury pastry, including lots of tips and tips, read my article on Savory Shortcrust Pastry!
I use a 35cm / 14 inch long Rectangular Tart Pan, but you can absolutely use a round one instead. This tart will feed 6 to 10 people, depending on if it is served as an entree, side or main.
French Leek Tart Filling
The tart filling combines two different elements:
- the veggies, pre-cooked in a pan
- the egg/cream liquid that will bind the vegetables
To make the filling, you will need (scroll down to recipe card below for all quantities):
- Leeks – washed and thinly chopped
- Small Brown Onion – thinly sliced
- Minced or Crushed Garlic – about 1 clove
- Butter – can be substituted with Olive Oil if preferred
- Heavy / Thickened Cream – I don’t recommend using a light cream
- Grated Gruyère Cheese
- Salt, Pepper and Cumin Powder – or your choice of spices.
More Leeks Recipes:
How to make Leek and Onion Tart Filling
Again, making the filling comes in two steps: pre-cooking the veggies then mixing it with the rest of the filling ingredients.
- Wash and chop/slice the Leeks and Onion. Make sure you use all parts of the Leeks (except the base) – both the white and green parts.
- Heat up a non-stick pan and melt the Butter. Add the Leeks, Onion and Garlic and cook for 5 to 10 minutes, or until soft. The Onion Slices should be translucent. Set aside away from the stove.
- In a separate bowl, whisk together the Eggs, Cream and Spices. Mix in the pre-cooked Leeks/Onion, then stir in the grated Gruyere.
- Pour the filling over the blind-baked pastry and place back in the oven for 25 to 35 minutes. The filling should be set and the leeks lightly golden.
I mixed both the cooked veggies and the egg/cream mixture, but you can also place the Leeks/Onion at the bottom of the pre-baked pastry and cover it with the Egg/Cream mixture – it is up to you.
You may need to spread the veggies in the pastry a little bit. Simply use a spoon to spread the filling evenly if needed.
Yes, it is better to blind bake the pastry for 10 to 15 minutes here. The filling will be rather liquid so blind-baking it will help to bake the crust and avoid being soggy.
I did not use baking beads or weights to blind bake the pastry as the idea is to dry out the bottom of the crust.
If not served straight away, leave this tart to cool down then cover and keep in the fridge. It will last for up to 3 days in the fridge. This tart can also be made in advance, preferably up to 1 day in advance.
To re-heat this tart, cover with foil and place in a warm over for 10 to 15 minutes. Individual slices can also be re-heated in the microwave for a minute.
This tart will freeze really well. You can freeze the whole tart, or individual slices. Make sure it is completely cool, then wrap with one layer of plastic wrap and one layer of aluminium foil. This savory tart can be kept in the freezer for up to 2 months.
To thaw, cover with foil only and place in the oven for about 20 minutes. Leaving it in the fridge overnight will also speed up the reheating process.
Note that if you are making this recipe to freeze it, I highly recommend under-baking it a bit to avoid burning it when you re-heat it.
More Savoury Tarts Recipes:
- Beetroot and Goats Cheese Tart
- Spinach and Feta Quiche
- Onion, Fig and Feta Tart
- Cheese and Tomato Quiche
- Tomato, Basil and Feta Galette
- Asparagus and Feta Quiche
- Spinach and Mushroom Quiche
- Broccoli Quiche with Cheddar Cheese
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Leek Tart with Gruyere and Onions
Savory Shortcrust Pastry
- 180 gr (1 cup + 2 tbsp) Plain Flour
- 1 pinch Salt
- 90 gr (6 tbsp) Unsalted Butter – cold
- 60 ml (1/4 cup) Cold Water
Leek Tart Filling
- 2 Leeks
- 1 small Brown Onion
- 30 gr (2 tbsp) Unsalted Butter – or Olive Oil
- 1/2 tsp Minced Garlic
- 2 Eggs
- 120 ml (1/2 cup) Heavy / Thickened Cream
- 1 tsp Table Salt
- 1/2 tsp Pepper
- 1 tsp Ground Cumin – optional
- 35 gr (1/3 cup) Grated Gruyere Cheese
Savory Shortcrust Pastry
- Place the Flour and Salt in the bowl of your food processor. Add the cold Butter cut into small cubes and blend until it forms small crumbs (1).
- Slowly add the cold Water, a little bit at the time and blending between each addition. Stop adding the water as soon as the dough comes together (2).
- Transfer over a lightly floured sheet of baking paper and bring together into a disk. Place a second sheet of baking paper over it and roll the pastry into a large rectangle (3) using a rolling pin. Place in the fridge to rest for at least 30 minutes to 1 hour.
- Remove the two layers of baking paper and line your baking pan with the Shortcrust Pastry. Poke small holes all over the pastry with a fork, then place back in the fridge for 30 minutes to 1 hour. Put the Pastry in the freezer for the last 15 minutes before baking it.
- Blind Bake the Pastry for 10 to 15 minutes (4) in an oven preheated on 180'C/350'F, then set aside while you prepare the filling.
Leek Tart Filling
- Wash the Leeks and chop into thin slices. Thinly slice the Brown Onion.
- Place the Butter into a non-stick pan on medium heat. When hot, sautee the chopped Leeks, sliced Onion and Minced Garlic for about 5 minutes. The onions should be translucent. Remove from the stove.
- In a separate bowl, whisk together the Eggs, Heavy Cream, Salt, Pepper and Cumin. Add the pre-cooked Leeks/Onion and mix in the Grated Gruyere.
- Pour over the pre-baked pastry and bake for another 25 to 35 minutes. The leeks should be lightly golden and the filling set (5). Serve warm.
- You shouldn’t see any large pieces of butter – it should be relatively well distributed.
- You may need a little bit more or less water, so make sure to add it gradually.
- If using a round tart tin, roll the pastry into a large circle. Check with your tin if you have rolled the dough enough by placing it over the rolled pastry.
- You want the bottom of the pastry to have partially baked.
- If moving the tin, you shouldn’t see the filling jiggle or move.