Enjoy this caramelized onion gruyere tart for brunch or serve it as an appetizer at your next get-together! It’s sweet, savory, delicious, and super easy to make!
Round out this meal with this delicious creamy garlic salmon and shrimp!
This recipe is made with just 5 ingredients! I love serving this during the holidays alongside a charcuterie board. It’s elegant, delicious, and so easy to put together.
WHAT’S IN THIS TART?
See the recipe card below for ingredient quantities and complete instructions.
- Puff Pastry – Puff pastry can typically be found in the frozen section of most grocery stores. Look for it alongside other frozen dough products or pastry items. It might be labeled as “puff pastry” or “frozen pastry dough.”
- Cheese -I love gruyere cheese for this recipe but feel free to use whatever cheese you prefer.
- Onions – White or yellow onions work for this recipe. Avoid using red onions.
- Butter – Unsalted or salted butter works.
TOP TIPS
- Slice the onions thinly and evenly to ensure they cook and caramelize evenly.
- Caramelizing onions takes time, so be patient. Cook them over low to medium-low heat to gently coax out their natural sugars without burning them. Stir occasionally to prevent sticking and ensure even caramelization.
- Season the onions with salt once they’re done cooking.
- Thaw the frozen puff pastry for 15-20 minutes before baking.
STORAGE
I highly recommend eating this 10 minutes after it comes out of the oven, but if you have some leftovers, place them in an air-tight container and keep at room temperature for 1-2 days.
Tried this onion gruyere tart? Please leave a star ⭐️⭐️⭐️⭐️⭐️ rating in the recipe card below and/or a review in the comments section further down the page. And consider following me on Facebook or Pinterest!
Caramelized Onion Gruyere Tart
Ingredients
- 1 sheet puff pastry
- 3 large onions thinly sliced
- 1 ½ cups gruyere cheese shredded
- 4 tablespoons butter
- salt to taste
- 1 egg
- 1 tablespoon water
Instructions
- Add the butter to a large pot and allow it to melt completely.
- Stir in the onions and cook for about 1 hour over medium-low heat. Make sure to stir occasionally. In the middle of the cooking process, add a splash of water to deglaze the bottom of the pot.
- Once the onions are nice and caramelized, turn off the heat and season them with salt, but not too much because the gruyere cheese is very salty.
- Line a baking sheet with parchment paper and pre-heat your oven to 375 degrees F.
- Place the thawed puff pastry on the baking sheet and pierce it several times with a fork.
- Add the cheese and then the caramelized onions all over the tart, leaving a ½ inch border. Whisk the egg and water, brush the border with the egg wash, and then bake for 20 minutes.
- Allow the tart to cool for 5-10 minutes, slice it into squares, and enjoy!
Notes
- Slice the onions thinly and evenly to ensure they cook and caramelize evenly.
- Caramelizing onions takes time, so be patient. Cook them over low to medium-low heat to gently coax out their natural sugars without burning them. Stir occasionally to prevent sticking and ensure even caramelization.
- Season the onions with salt once they’re done cooking.
- Thaw the frozen puff pastry for 15-20 minutes before baking.
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