Caramelized Onion Tart Recipe

Published on June 1st 2024 by Sarah Leadon.
Last updated on June 10th 2024
This recipe, developed through the collective effort of at least six experts, underwent meticulous research and testing for over three months. Learn more about our process in the art and science behind our recipes. This post may contain affiliate links. Read our Disclosure Policy.
Close up view of Caramelized Onion Tart

Elevate your appetizer game with this fancy yet fuss-free Caramelized Onion Tart! We're talking about a flaky puff pastry brushed with a luscious garlic-thyme vegan butter, and then piled high with creamy coconut sauce, sweet caramelized onions, and bright cherry tomatoes. You'll be hooked on the rich, buttery flavors with one bite of the golden-baked deliciousness. These elegant tarts make the perfect impressive starter for intimate dinner parties. Pair them with our zesty Black Bean Tostadas or Artichoke Bruschetta if you want more appetizers for your dinner party.

How healthy are caramelized onions?

Caramelized onions can be a healthy addition to your diet. The caramelization process increases the antioxidant content, providing anti-inflammatory benefits. Onions are also a good source of fiber to aid digestion and quercetin, which may help reduce disease risk.

What do caramelized onions taste like?

Caramelized onions have a delightfully complex flavor that's equal parts sweet and savory. As the natural sugars caramelize, the onions develop a rich, almost candy-like sweetness balanced by an intense umami savoriness.

Do you add salt when caramelizing onions?

Yes, adding salt is recommended when caramelizing onions. The salt helps draw out moisture from the onions, which is necessary for the caramelization process to occur properly. Without salt, it can take much longer for the onions to develop that rich, sweet, caramelized flavor.

Why do you add baking soda to caramelize onions?

Adding a small amount of baking soda to onions helps speed up the caramelization process. The baking soda raises the pH level, making the onions more alkaline and allowing the natural sugars to caramelize and brown more quickly.

Author: Sarah Leadon
Average: 5 (2 votes)
Total rating includes sum of all comments and anonymous votes.

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Time & Serves

Prep Time
10 mins
Cook Time
40 mins
Total Time
50 mins
3 persons


  • 1 batch of Quick Caramelized Onions

  • 3 tablespoons Unsalted Butter

  • 2 cloves Garlic, minced

  • 1 tablespoon Fresh Thyme

  • 4 tablespoons Coconut Cream

  • 1 whole sheet of Puff Pastry, thawed

  • 1 cup Cherry Tomatoes, quartered

  • 1/4 teaspoon Kosher Salt

  • 1/2 teaspoon Black Pepper


Prepare the quick caramelized onions and set them aside to cool.

Caramelized onions

Preheat your oven to 375 °F.

Prepare oven for baking

To make the caramelized onion tart, place the butter into a small skillet. Set it over medium-low heat and heat it until the butter melts.

Melting the butter

Add the garlic and thyme and cook it for 1–2 minutes until fragrant. Remove the butter mixture from the heat. Set it aside.

Cook the garlic and thyme into the melted butter

Dust your countertop with flour, then place the puff pastry on top of it and unfold it into an even layer. Dust your rolling pin with flour, and roll the whole sheet of puff pastry out slightly.

Prepare the puff pastry

Cut the puff pastry the whole sheet of puff pastry into 3 even pieces using a sharp knife.

Cutting puff pastry into 3 pieces

Place each puff pastry rectangle onto a parchment-lined baking sheet in an even layer, then pierce each puff pastry all over with a fork.

Prepare the puff pastry into the baking pan

Brush each puff pastry with the butter mixture, then top with 1 tablespoon of coconut cream, leaving a 1/2-inch border. Fold each end of the puff pastry over slightly to form a crust and create a pocket for the caramelized onions and tomatoes. Repeat with the remaining puff pastry.

Bushing puff pastry with butter mixture and coconut cream

Sprinkle the caramelized onions and tomatoes on top. Sprinkle each caramelized onion tart with salt and black pepper.

Add caramelized onion and tomatoes on top of the puff pastry

Bake the caramelized onion tarts for 15–17 minutes until the puff pastry is golden brown.

Cooked caramelized onion tart

Brush the edges of the caramelized onion tarts with the remaining butter mixture, then let them cool for 2–3 minutes before serving.

Serving caramelized onion tart
Sarah Leadon

Delve into the fusion of food and mood with Sarah. Discover the emotional journey within each recipe. Beyond the kitchen, she's an avid reader and music lover, lost in the rhythms of life.

More posts by Sarah Leadon

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flaky pastry, vegan tart, caramelized onion recipe, elegant appetizer, plant-based dish, party appetizer, savory tart, thyme flavor, puff pastry tart, dairy-free recipe

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Sarah Leadon

Delve into the fusion of food and mood with Sarah. Discover the emotional journey within each recipe. Beyond the kitchen, she's an avid reader and music lover, lost in the rhythms of life.

More posts by Sarah Leadon