Sweet Caramelized Onion Tart

Name: Sweet Caramelized Onion Tart
Prep time: 30 min
Cook time: 40 min
Total time: 1 h 10 min
Yield: 8 servings
Ingredients: 1 sheet of puff pastry (thawed); 3 large onions (yellow or red), thinly sliced; 2 tablespoons olive oil; 1 teaspoon sugar; Salt and pepper to taste; 1 cup ricotta cheese; 1 egg (beaten); 1 tablespoon fresh thyme leaves

Highlighted under: Classic Comfort Recipe Ideas

I absolutely love making this Sweet Caramelized Onion Tart for gatherings and family dinners. The rich, savory flavor of the caramelized onions paired with the flaky pastry is simply irresistible. I often serve this tart warm, and it's always a hit as an appetizer or a side dish. The combination of sweetness from the onions and the creaminess of the cheese creates a delightful experience. Trust me, once you try this recipe, it will become a staple in your kitchen.

Created by

Emily

Last updated on 2026-01-08T15:06:44.201Z

When I first experimented with this Sweet Caramelized Onion Tart, I was amazed by how the onions transformed during cooking. The slow caramelization process brings out their natural sweetness, creating layers of flavor that enhance the tart. I recommend using a mix of yellow and red onions for depth. Always allow the onions to cool slightly before spreading them on the pastry; this prevents the crust from becoming soggy.

I also discovered that adding a sprinkle of thyme really elevates the taste. It provides a beautiful earthiness that balances the sweetness, resulting in a well-rounded dish. Every bite is a perfect harmony of flavors, and it pairs wonderfully with a crisp salad or a glass of white wine.

        Why You'll Love This Recipe
        Irresistibly flaky crust complements the sweet onions
A touch of thyme adds an aromatic depth
Perfect for sharing with friends or enjoying alone

      

The Art of Caramelization

Caramelizing onions is a technique that transforms their sharpness into a sweet, rich flavor, bringing depth to your Sweet Caramelized Onion Tart. Begin with medium heat to allow the onions to soften slowly without burning. Stir them occasionally, allowing them to cook evenly and develop a golden-brown color. If they stick to the pan, deglaze with a splash of water or broth to prevent any bitterness from forming.

The addition of a teaspoon of sugar during the caramelization process accelerates the browning, enhancing the natural sweetness of the onions. However, if you're watching your sugar intake, you can skip this step and simply let the onions cook until they are deeply caramelized. Aim for a rich, golden hue, as this indicates they'll impart a wonderful flavor to your tart.

Choosing Your Cheese

Ricotta cheese is mild and creamy, providing a perfect base for the caramelized onions, but feel free to experiment. Mascarpone or a goat cheese can add tanginess and enhance the overall flavor profile. If you prefer a stronger cheese presence, consider adding a sprinkle of grated Parmesan or sharp cheddar on top of the ricotta layer before adding the onions for an extra flavor kick.

For a lighter alternative, cottage cheese can be blended until smooth and substituted for ricotta. This adjustment will alter the texture slightly, but it will keep the tart fresh and airy. Regardless of the cheese choice, ensure it is at room temperature before spreading it on the pastry; this helps it adhere better and allows for even melting during baking.

Ingredients

Gather the following ingredients before you start:

For the Tart

1 sheet of puff pastry (thawed)
3 large onions (yellow or red), thinly sliced
2 tablespoons olive oil
1 teaspoon sugar
Salt and pepper to taste
1 cup ricotta cheese
1 egg (beaten)
1 tablespoon fresh thyme leaves

Make sure all ingredients are at room temperature before you begin.

Instructions

Follow these steps to create your Sweet Caramelized Onion Tart:

Caramelize the Onions

In a large skillet, heat the olive oil over medium heat. Add the sliced onions, salt, and sugar. Cook, stirring occasionally, until the onions are soft and golden, about 25-30 minutes.

Prepare the Pastry

Preheat the oven to 400°F (200°C) and roll out the puff pastry on a lightly floured surface. Place it in a tart pan and prick the bottom with a fork.

Assemble the Tart

Spread the ricotta cheese evenly over the base of the pastry. Top with the caramelized onions, and drizzle with the beaten egg. Sprinkle with thyme leaves.

Bake the Tart

Bake in the preheated oven for 25-30 minutes until the pastry is golden and puffed. Let it cool for a few minutes before slicing.

Serve warm or at room temperature. Enjoy!

Pro Tips

For a deeper flavor, consider adding a splash of balsamic vinegar to the onions while caramelizing.

Make-Ahead Tips

You can prepare the caramelized onions a day in advance and store them in an airtight container in the fridge. This not only saves time but also intensifies the flavors as they cool. On the day of serving, simply reheat the onions on low heat before assembling your tart to regain their lovely texture and warmth.

If you want to make the tart completely ahead of time, consider assembling it without baking and store it covered in the fridge. When you're ready to serve, bake directly from the cold state, but add an extra 5-10 minutes to the baking time to ensure a perfectly golden crust.

Serving Suggestions

This Sweet Caramelized Onion Tart pairs beautifully with a simple green salad or a fresh arugula salad tossed in a lemon vinaigrette, providing a refreshing contrast to the savory flavor of the tart. Additionally, consider serving it with a dollop of crème fraîche or a drizzle of balsamic reduction for an elegant touch.

As a lovely brunch option, serve warm alongside a selection of artisanal breads and spreads. You can even slice it into smaller pieces for delightful hors d'oeuvres at a party. The versatility of this tart makes it suitable for various occasions, whether as an appetizer, a side dish, or a light main course complemented by a glass of white wine.

Questions About Recipes

→ Can I make this tart ahead of time?

Yes, you can prepare the caramelized onions and pastry in advance. Assemble and bake just before serving.

→ What can I substitute for ricotta cheese?

Mascarpone or cream cheese can work as substitutes for a creamier texture.

→ Can I freeze the tart?

Yes, it freezes well. Just bake it fully and let it cool before wrapping tightly and freezing.

→ How do I store leftovers?

Store leftovers in an airtight container in the refrigerator for up to three days.