I turned humble leeks and sweet onions into a show-stopping Vegetarian Leek Tart that fans of Savory Tarts will want to make for breakfast, brunch or dinner, and it even freezes beautifully.

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I make this Savory Leek Tart when I want something that looks fancy but doesn’t pretend to be complicated. The sweet edge of the leeks meets pockets of nutty Gruyere cheese and somehow every bite tells you a little secret, you know?

As a Tartas Saladas kind of dish it moves from breakfast to dinner like it owns the place, people grab a slice and go silent, which is always a good sign. I never plan perfectly, I just put it together and it works more often than not, so if you like food that surprises you, this one will.

Ingredients

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Leeks: mild onion taste, lots of fiber, adds sweet savory depth when slow cooked.
Onion: sharp, caramelizes to sweetness, supplies carbs and flavor, helps balance richness.
Gruyere: nutty, melty, high in protein and calcium, gives savory, rich cheesiness.
Butter: adds flaky texture and buttery flavor, high in fat so use thoughtfully.
Eggs: bind the filling, provide protein and structure, make it custardy and golden.
Cream: it enriches custard, very creamy and rich, adds fat, silkiness and slight tang.
Flour: forms the crust structure, mostly carbs, gives tender, slightly crisp base.

Ingredient Quantities

1 1/4 cups (160 g) all purpose flour

1/2 tsp fine sea salt

8 tbsp (115 g) unsalted butter, very cold, cut into small cubes

2 to 3 tbsp ice water

3 large leeks, white and light green parts only, thinly sliced (about 3 cups)

1 medium yellow onion, thinly sliced

2 tbsp unsalted butter

1 tbsp olive oil

3 large eggs

1 cup (240 ml) heavy cream or crème fraîche

1 1/2 cups (150 g) Gruyere cheese, grated

1 tsp Dijon mustard (optional)

1 tsp fresh thyme leaves or 1/2 tsp dried thyme

1 tsp kosher salt, plus more to taste

1/2 tsp freshly ground black pepper

Pinch of ground nutmeg (optional)

1 beaten egg for brushing the crust (optional)

How to Make this

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1. Make the shortcrust: in a bowl mix 1 1/4 cups (160 g) all purpose flour with 1/2 tsp fine sea salt, cut in 8 tbsp (115 g) very cold cubed unsalted butter until mixture looks like coarse crumbs with some pea sized bits, add 2 to 3 tbsp ice water little by little until the dough just holds together; form a disk, wrap and chill 30 minutes. don’t overwork it or it’ll be tough.

2. Preheat oven to 375°F (190°C). On a lightly floured surface roll the chilled dough into a 9 to 10 inch circle, fit into a tart pan and trim the edges, prick the bottom a few times with a fork, then chill the shell in the fridge 10 to 15 minutes so it keeps shape.

3. Blind bake the shell: line with parchment and pie weights or dried beans and bake 15 to 20 minutes until the edges are set, remove weights and parchment, optionally brush the crust with the beaten egg and return to the oven 3 to 5 minutes to set the glaze. set aside.

4. Prep the veg: trim and thinly slice 3 large leeks (white and light green only) and 1 medium yellow onion, rinse the leeks well if they look sandy. Heat 2 tbsp unsalted butter and 1 tbsp olive oil in a skillet over medium, add the leeks and onion with 1 tsp kosher salt, 1/2 tsp freshly ground black pepper and 1 tsp fresh thyme (or 1/2 tsp dried), cook until soft and most of the moisture has evaporated, about 8 to 12 minutes. let cool a bit.

5. Make the custard: in a bowl whisk 3 large eggs with 1 cup (240 ml) heavy cream or crème fraîche, stir in 1 tsp Dijon mustard if using, a pinch of ground nutmeg if using, and taste for salt; remember you already added some salt to the veggies so be light at first.

6. Finish the filling: fold the cooled leek and onion mixture into the egg mixture, then stir in 1 1/2 cups (150 g) grated Gruyere cheese until evenly distributed.

7. Assemble and bake: pour the filling into the partially baked tart shell, smooth the top and sprinkle a little extra Gruyere if you like, bake at 375°F (190°C) for 25 to 35 minutes until the center is set and the top is golden; a gentle jiggle in the center is fine, it will finish setting as it cools.

8. Rest, serve and store: let the tart cool 10 to 15 minutes before slicing so it firms up; serve warm or at room temp. To freeze: you can freeze a fully baked tart wrapped tightly for up to 2 months and reheat at 350°F (175°C) about 20 to 30 minutes, or freeze an unbaked assembled tart and bake from frozen adding about 10 to 15 minutes to the baking time.

9. Quick tips: use crème fraîche for a tangier custard, grate the Gruyere fresh for best melt and flavor, don’t rush reducing the leeks or the filling can be watery, and if you want a shinier crust brush with the beaten egg before the final bake.

Equipment Needed

1. Large mixing bowl (for the dough and the custard)
2. Pastry cutter or small food processor (to cut the cold butter into the flour)
3. Rolling pin and a lightly floured surface (to roll the chilled dough out)
4. 9 to 10 inch tart pan with removable bottom (makes trimming and unmolding easy)
5. Baking sheet plus parchment paper and pie weights or dried beans (for blind baking)
6. 10 to 12 inch skillet (for softening the leeks and onion)
7. Box grater (for grating the Gruyere)
8. Whisk and rubber spatula or wooden spoon (to mix the custard and fold in the veggies)
9. Pastry brush and fork (fork to prick the crust, brush to glaze the crust with beaten egg)

FAQ

Q: How do I stop the crust from getting soggy?

A: Parbake the crust first – prick it with a fork, line with parchment and pie weights or dried beans, bake at 375°F (190°C) about 12-15 minutes, remove weights and bake 3-5 more minutes. Also cook the leeks and onion until most liquid is gone, drain and cool before filling, that really helps keep it crisp.

Q: Can I make the crust or tart ahead of time?

A: Yes. Dough can be made and chilled up to 2 days or frozen up to 1 month. Fully baked tart keeps in the fridge 3-4 days. For best texture reheat slices in a 350°F (175°C) oven 10-15 minutes to get the crust crisp again.

Q: What cheese can I use if I don't have Gruyere?

A: Good swaps are Comté, Emmental or a nutty Swiss. Sharp cheddar works too but changes the flavor. Pick a cheese that melts well for the best gooey filling.

Q: Can I use crème fraîche instead of heavy cream?

A: Absolutely. Crème fraîche makes the filling a bit tangier and richer, use the same amount. If it seems too thick you can thin it with a tablespoon of milk or cream.

Q: How should I clean and prepare the leeks so they aren't gritty?

A: Slice the white and light green parts then soak them in cold water, swish to let grit fall to the bottom, lift them out with a slotted spoon and drain well. Repeat if needed, leeks hide sand in the layers.

Q: Can I make this tart vegan or dairy free?

A: You can try – use vegan butter for the crust, a cashew or soy cream for the filling, a flax or aquafaba egg replacer, and a good melting vegan cheese. Texture and flavor will be different but it works in a pinch.

Savory Leek Tart With Onion And Gruyere Cheese Recipe Substitutions and Variations

Gruyere: If you can’t find Gruyere, use Comte or Emmental, same amount by weight. They melt the same and have a similar nutty profile, just a hair milder or sharper depending on the wheel.
Heavy cream or crème fraîche: Swap with sour cream thinned with milk or full fat Greek yogurt loosened with a bit of milk. For 1 cup cream use 1 cup sour cream plus 2 to 3 tbsp milk, whisk till smooth, you’ll still get a rich custard.
Leeks: No leeks? Use 1 large sweet onion plus 3 to 4 scallions, thinly sliced, and cook them like the leeks. Or use 8 to 10 shallots for a sweeter, more delicate onion taste.
Cold butter for the crust: Use chilled vegetable shortening or lard, or mix half butter and half shortening. Use equal weight as the recipe calls for, the crust will be flaky though pure butter gives a nicer flavor.

Pro Tips

1) Keep the butter ice cold and work fast when making the dough. Little pea sized bits of butter are good because they make the crust flaky, but if the dough warms up chill it again for a few minutes. Don’t overmix or you’ll end up with a tough crust.

2) When you cook the leeks and onions, salt them early and let them really reduce until most of the moisture is gone. If they still seem wet after cooling, squeeze them in a clean towel so your custard does not get watery.

3) Grate the Gruyere fresh instead of using pre shredded cheese, it melts way better and tastes brighter. Taste the custard before you pour it in because the cheese and veggies add salt, so go light on added salt at first.

4) For a shiny, pretty crust brush the edges with the beaten egg and give it a few extra minutes in the oven to set. And let the tart rest about ten to fifteen minutes before slicing so the center firms up, it slices cleaner that way.

5) You can freeze either a fully baked tart or the assembled unbaked one. Wrap tightly and when reheating use a moderate oven so the filling warms through without drying out, add about ten to fifteen extra minutes if you bake it straight from frozen.

Savory Leek Tart With Onion And Gruyere Cheese Recipe

Recipe by Francis Mead

0.0 from 0 votes

I turned humble leeks and sweet onions into a show-stopping Vegetarian Leek Tart that fans of Savory Tarts will want to make for breakfast, brunch or dinner, and it even freezes beautifully.

Servings

servings

Calories

599

kcal

Equipment: 1. Large mixing bowl (for the dough and the custard)
2. Pastry cutter or small food processor (to cut the cold butter into the flour)
3. Rolling pin and a lightly floured surface (to roll the chilled dough out)
4. 9 to 10 inch tart pan with removable bottom (makes trimming and unmolding easy)
5. Baking sheet plus parchment paper and pie weights or dried beans (for blind baking)
6. 10 to 12 inch skillet (for softening the leeks and onion)
7. Box grater (for grating the Gruyere)
8. Whisk and rubber spatula or wooden spoon (to mix the custard and fold in the veggies)
9. Pastry brush and fork (fork to prick the crust, brush to glaze the crust with beaten egg)

Ingredients

1 1/4 cups (160 g) all purpose flour
1/2 tsp fine sea salt
8 tbsp (115 g) unsalted butter, very cold, cut into small cubes
2 to 3 tbsp ice water
3 large leeks, white and light green parts only, thinly sliced (about 3 cups)
1 medium yellow onion, thinly sliced
2 tbsp unsalted butter
1 tbsp olive oil
3 large eggs
1 cup (240 ml) heavy cream or crème fraîche
1 1/2 cups (150 g) Gruyere cheese, grated
1 tsp Dijon mustard (optional)
1 tsp fresh thyme leaves or 1/2 tsp dried thyme
1 tsp kosher salt, plus more to taste
1/2 tsp freshly ground black pepper
Pinch of ground nutmeg (optional)
1 beaten egg for brushing the crust (optional)

Directions

Make the shortcrust: in a bowl mix 1 1/4 cups (160 g) all purpose flour with 1/2 tsp fine sea salt, cut in 8 tbsp (115 g) very cold cubed unsalted butter until mixture looks like coarse crumbs with some pea sized bits, add 2 to 3 tbsp ice water little by little until the dough just holds together; form a disk, wrap and chill 30 minutes. don’t overwork it or it’ll be tough.
Preheat oven to 375°F (190°C). On a lightly floured surface roll the chilled dough into a 9 to 10 inch circle, fit into a tart pan and trim the edges, prick the bottom a few times with a fork, then chill the shell in the fridge 10 to 15 minutes so it keeps shape.
Blind bake the shell: line with parchment and pie weights or dried beans and bake 15 to 20 minutes until the edges are set, remove weights and parchment, optionally brush the crust with the beaten egg and return to the oven 3 to 5 minutes to set the glaze. set aside.
Prep the veg: trim and thinly slice 3 large leeks (white and light green only) and 1 medium yellow onion, rinse the leeks well if they look sandy. Heat 2 tbsp unsalted butter and 1 tbsp olive oil in a skillet over medium, add the leeks and onion with 1 tsp kosher salt, 1/2 tsp freshly ground black pepper and 1 tsp fresh thyme (or 1/2 tsp dried), cook until soft and most of the moisture has evaporated, about 8 to 12 minutes. let cool a bit.
Make the custard: in a bowl whisk 3 large eggs with 1 cup (240 ml) heavy cream or crème fraîche, stir in 1 tsp Dijon mustard if using, a pinch of ground nutmeg if using, and taste for salt; remember you already added some salt to the veggies so be light at first.
Finish the filling: fold the cooled leek and onion mixture into the egg mixture, then stir in 1 1/2 cups (150 g) grated Gruyere cheese until evenly distributed.
Assemble and bake: pour the filling into the partially baked tart shell, smooth the top and sprinkle a little extra Gruyere if you like, bake at 375°F (190°C) for 25 to 35 minutes until the center is set and the top is golden; a gentle jiggle in the center is fine, it will finish setting as it cools.
Rest, serve and store: let the tart cool 10 to 15 minutes before slicing so it firms up; serve warm or at room temp. To freeze: you can freeze a fully baked tart wrapped tightly for up to 2 months and reheat at 350°F (175°C) about 20 to 30 minutes, or freeze an unbaked assembled tart and bake from frozen adding about 10 to 15 minutes to the baking time.
Quick tips: use crème fraîche for a tangier custard, grate the Gruyere fresh for best melt and flavor, don’t rush reducing the leeks or the filling can be watery, and if you want a shinier crust brush with the beaten egg before the final bake.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.