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Savory Onion Gruyère Tart

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This flaky tart takes cozy soup vibes to the next level with sweet caramelized onions, Gruyère cheese, and fresh thyme in a creamy filling. Golden crust meets a bubbly cheesy top, perfect for casual meals or special gatherings.
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alicia in the kitchen
Updated on Sun, 08 Jun 2025 12:23:01 GMT
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Onion Gruyère Tart | tasteofsavor.com

Want something comforting with a little French flair? Grab some thin onion slices, melty Gruyère, and fresh herbs. This twist on a French classic packs tons of flavor and feels special without being fussy.

INGREDIENTS

  • Kosher Salt: 1 teaspoon, sprinkle this on the onions and the dough for good seasoning.
  • Unsalted Butter: 3 tablespoons, diced to melt nicely throughout the filling.
  • Heavy Cream: 1 tablespoon, for brushing the onions just before everything goes in the oven.
  • Sweet Onions: 1 ¼ lbs (about 3 onions), peeled and thinly sliced—these make up your main layer.
  • Fresh Chives: 2 teaspoons, chopped for a little greenery and extra zip.
  • Fresh Thyme: 1 ½ teaspoons, minced to add some earthy vibes.
  • Gruyère Cheese: 1 cup, shredded to create a cheesy layer that melts and bubbles.
  • Ice Water: ½ cup, use this for helping the dough come together without it getting tough.
  • Cold Unsalted Butter: 12 tablespoons (1 ½ sticks), chopped and chilled so your crust bakes up crisp.
  • Sugar: 1 tablespoon, just enough to keep the crust tasty and not bland.
  • Kosher Salt: ½ teaspoon, season your crust and tie all the flavors together.
  • All-Purpose Flour: 2 cups, the starting point for your tart's base.

INSTRUCTIONS

Step 8:
When it's out of the oven, let it chill for a few, then slice it how you like. Enjoy it warm or room temp.
Step 7:
Slide the tray into a 400°F (200°C) oven for about 40 minutes, watching for a deep golden color on top. If the outer edges darken fast, cover those with foil.
Step 6:
Brush heavy cream on the onion layer, pop little butter bits all over, dust with a bit more salt.
Step 5:
Set up your onion slices diagonally over the dough, keeping them overlapping just a bit. Toss on the cheese right out to the sides, then sprinkle those chopped herbs on top.
Step 4:
Roll out that dough into a big rectangle (about 10 by 14 inches) and lay it on a parchment-lined baking sheet.
Step 3:
Cut off the onion skins, chop them in half, and slice thin so you get those lovely half-moon shapes.
Step 2:
Dribble in the ice water and mix or pulse it just until clumps form. Shape into a disc, wrap it tight, and pop in the fridge for at least half an hour—or freeze if you're not ready yet.
Step 1:
Tip the flour, salt, and sugar into a big bowl or food processor. Drop in the butter and work it until it feels like sand with small chunks.

Serving and Storage Tips

  • Slice and serve however you want—squares, strips, or wedges. It's good warm or left out to cool.
  • This goes awesome alongside a crisp salad or a glass of white to keep things French and fun.
  • Stash any extras in a container with a tight lid, and it'll be fine in the fridge for three days.
  • To re-crisp later, toss it back in a 350°F oven for 10–12 minutes.

Tips from Well-Known Chefs

  • Ina Garten likes using the best butter she can find for a tastier base and lift.
  • Julia Child says keeping your dough super cold helps your crust bake up nice and flaky.
  • Gordon Ramsay recommends a little splash of balsamic on the onions for next-level flavor.

VARIATIONS

  • Slide in sautéed mushrooms or caramelized leeks to change up the layers and deepen the flavor.
  • If you want to bulk it up, add some crispy bits of bacon or pancetta with the onions.
  • Want it even lighter? Grab puff pastry instead of classic dough for the crust.

Onion Gruyère Tart

Flaky crust with caramelized onions, Gruyère, and fresh herbs. Baked till golden and bubbly—a delicious French-inspired treat.

Prep Time
40 Minutes
Cook Time
40 Minutes
Total Time
80 Minutes
By: Alicia

Category: Appetizers

Difficulty: Intermediate

Cuisine: French

Yield: 1 tart

Dietary: Vegetarian

Ingredients

01 ½ cup ice-cold water.
02 ½ teaspoon salt, kosher preferred.
03 1 cup shredded Gruyère cheese (about 4 oz).
04 1 tablespoon of sugar.
05 2 teaspoons minced fresh chives.
06 12 tablespoons diced cold butter (1 ½ sticks).
07 1 tablespoon heavy cream.
08 1 ¼ pounds of sweet onions (about three medium-sized ones).
09 1 ½ teaspoons minced fresh thyme.
10 3 tablespoons small cubes of butter.
11 2 cups regular all-purpose flour.
12 1 teaspoon kosher salt, divided.

Instructions

Step 01

In a large mixing bowl or food processor, mix together the flour, sugar, and kosher salt.

Step 02

Add the butter pieces and blend until the mixture looks like coarse crumbs.

Step 03

Slowly add the chilled water while mixing until the dough starts coming together.

Step 04

Wrap the dough in some cling film and chill in the fridge for half an hour, or freeze for a later time.

Step 05

Cut the onions into thin, crescent-shaped slices after peeling and halving them.

Step 06

Shape the dough into a 10x14-inch rectangle, then transfer it to a baking tray lined with parchment paper. Arrange the onion slices diagonally, overlapping slightly.

Step 07

Scatter the grated Gruyère all the way to the edges of the dough. Then, add the chives and thyme evenly on top.

Step 08

Lightly coat the onions with a brush dipped in heavy cream.

Step 09

Dot the onions with small cubes of butter.

Step 10

Sprinkle over the second portion of kosher salt.

Step 11

Bake at 400°F (200°C) for roughly 40 minutes or until the pastry becomes golden and the onions soften completely.

Step 12

If you see the pastry edges browning too much, wrap foil around them while baking.

Step 13

Let it rest for a few minutes to cool down. Slice it into portions — squares, slices, or strips — and enjoy while warm or at room temp.

Notes

  1. For deeper flavor, try cooking the onions until caramelized before adding them.
  2. Serve it alongside an easy green salad for a great combo.

Nutrition Facts (Per Serving)

It is important to consider this information as approximate and not to use it as definitive health advice.
  • Calories: 350
  • Total Fat: 22 g
  • Total Carbohydrate: 30 g
  • Protein: 8 g