French Onion Tart


Full-flavored Onion Tart

This French-inspired onion tart is characterized by its taste of juicy, caramelized onion, fine herbs, the full-bodied taste of Dijon mustard and strong Gruyere cheese.

You can prepare the cake perfectly in advance – it’s perfect for brunch!

Discover a new taste

I only knew German rustic onion tarts made on a tray with yeast dough.

When I was having a baking day with my friend Claudia, she brought an onion tart for lunch. And what can I say, I immediately asked her for the recipe!

The tart was just amazingly delicious. The caramelized onions together with the cheese make a perfect match!

It’s regularly on my menu now, which my husband is not so enthusiastic about because he doesn’t like onions – all for me 🙂

Combine with a fresh leaf salad for a full meal!

Onion Tart - Jennifer Vahlbruch
Onion Tart - Jennifer Vahlbruch
Onion Tart - Jennifer Vahlbruch
Onion Tart - Jennifer Vahlbruch
Onion Tart - Jennifer Vahlbruch

Ingredients you need

You need these ingredients to make your French Onion Tart.

Onion Tart - Ingredients - Jennifer Vahlbruch
Onion Tart - Jennifer Vahlbruch

Caramelized Onion Tart

Yield: 8 Pieces
Prep Time: 15 minutes
Cook Time: 1 hour 10 minutes
Additional Time: 1 hour 10 minutes
Total Time: 2 hours 35 minutes

If you love onions like me, you'll feel like you are in heaven.
The caramelized onion tart with its full taste should not be missing in any recipe collection!



  • 1 3/4 cups (240 grams) all-purpose flour
  • 2 pinch of salt
  • 2/3 cup (150 grams) unsalted butter, chilled and cut into small cubes
  • 1 egg yolk
  • 2 - 3 teaspoons cold water
  • Makes 15 OZ. (ca. 430 grams)

Onion topping

  • 3 large yellow onions
  • 2 tablespoons unsalted butter
  • 1 1/2 tablespoons Dijon mustard *
  • 3 Eggs
  • 1 cup (240 ml) heavy cream **
  • 1 cup (100 grams) gruyere cheese, grated ***
  • Salt and pepper
  • 1/2 teaspoon nutmeg
  • 3 teaspoons thyme leaves, picked
  • 1 teaspoon rosemary, chopped


  1. Sift the flour and salt into a large bowl.
  2. Add the butter and rub in with your fingertips until the mixture resembles bread crumbs.
  3. Add the egg yolk and a little cold water ( about 2-3 teaspoons) and mix with a flexible bladed knife until the dough just starts to come together.
  4. Bring the dough together with your hands and shape into a ball.
  5. You can also use a food processor to make the dough. For better results use the pulse button.
  6. Place the flour and butter in a food processor and process until the mixture resembles bread crumbs.
  7. Add the egg yolk and water and pulse until the mixture begins to come together to form a ball.
  8. Now wrap the dough plastic wrap and put it in the refrigerator to rest for at least 30 minutes.
  9. Preheat the oven to 200 celsius (400 Fahrenheit) and grease the baking tin (Ø 10 inches, 26 cm) with some butter.
  10. Now after the resting time roll out the pastry into a circle on a lightly floured surface and use to line a tart pan. Trim the edge and pinch around the pastry edge to make an even border raised slightly above the rim of the baking tin.
  11. Put in the refrigerator for 10 minutes.
  12. Line the tart with baking paper and fill with baking weights or beans. Bake for 10 minutes before removing the baking paper and weights and baking for a further 5 to 10 minutes or until the base is dry and lightly golden. Set aside to cool.
  13. To make the caramelised onions, heat a large frying pan over medium heat and add the butter. Now add the onions and cook for 10 minutes before adding the 2 tsp of the thyme and rosemary leaves, season with salt and pepper to taste. Reduce the heat a little bit and cook for a further 10 minutes until caramelised.
  14. Let it cool a bit before adding the mustard.
  15. In a bowl add the eggs along with the cream and whisk to combine. After that, add the cheese. Season with nutmeg, salt and pepper to taste.
  16. Place the onions on the base of the tart and spread evenly over the base. Topping with the egg mixture. Bake for 25 to 30 minutes or until the filling is just set.
  17. After baking let sit for at least 30 min with the oven door open.
  18. Serve with a fresh leave salad or just the tart.


* if you don't have Dijon mustard, you can use every other yellow mustard

** If you don't get heavy cream, you can also use whipping cream as well

*** You can use what cheese you prefer, but for me, gruyere is the best choice

Nutrition Information:
Serving Size: 8
Amount Per Serving: Calories: 484Total Fat: 37gSaturated Fat: 22gTrans Fat: 0.4gUnsaturated Fat: 13gCholesterol: 191mgSodium: 294mgCarbohydrates: 28gFiber: 2gSugar: 3.5gProtein: 12g

Did you make this recipe?

Please share a photo on Instagram and use the hashtag #jenstastytidbits

Make a perfect French onion tart

There is nothing in the recipe you have to pay attention to. It’s so quick and easy!


Find answers to the most common questions

No questions have been asked yet!

French Onion Tart Recipe Reviews

Learn what people are saying after they tried the quick and easy French Onion Tart.

No reviews are available yet!

Join my Foodie list for free

Don't miss any new recipe!

Stay in the know about new recipes, places, fine art and other content added to my website.

It's free and you can unsubscribe anytime.
I respect your privacy and will never ever sell your data.

Skip to Recipe

Pin It on Pinterest