Caramelized Onion Tart With Gruyere Recipe

I absolutely love this recipe because the combination of caramelized onions and Gruyere cheese on a flaky puff pastry crust is pure comfort food magic. Plus, it’s surprisingly simple to whip up, making it a perfect go-to for impressing friends at a dinner party or just treating myself to something delicious!

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This Caramelized Onion Tart with Gruyere is a marvelous combination of flavors. Using puff pastry keeps it simple, yet it has an elegant look.

The sweetness of three large caramelized onions balances the nutty Gruyere cheese. A hint of fresh thyme takes it over the top.

This is perfect to serve as an hors d’oeuvre at a dinner party, or alongside a salad for lunch.

Ingredients

Ingredients photo for Caramelized Onion Tart With Gruyere Recipe

Dough of the delicate pastry: Supplies rich taste of butter, serves up carbs for energy.

Extra virgin olive oil: This is a good type of olive oil—one that’s high in healthy fats.

It’s great for drizzling over your tart before serving; its natural bitterness enhances the tart’s richness.

Sweetness, fiber, and antioxidants are the properties that make onions so good for you.

Gruyere cheese: Full-flavored and about as protein-rich and calcium-laden as a food can get.

Egg: Gives shine, extra protein, and binding qualities.

Ingredient Quantities

  • 1 sheet puff pastry, thawed
  • 2 tablespoons olive oil
  • 3 large onions, thinly sliced
  • Salt and freshly ground black pepper, to taste
  • 1 teaspoon fresh thyme leaves
  • 1/4 cup heavy cream
  • 1 cup Gruyere cheese, grated
  • 1 egg, beaten (for egg wash)

Instructions

1. Your oven should be preheated to 400°F (200°C). A baking sheet should be lined with parchment paper.

2. On a surface lightly dusted with flour, roll out the puff pastry until it is somewhat larger than the baking sheet. Place the pastry on the baking sheet you prepared earlier.

3. In a sizable skillet, warm the olive oil over a medium flame. Toss in the sliced onions and cook, with an occasional stir, until they are fully caramelized and a gorgeous golden brown—about 25 to 30 minutes. Season with salt and contemporary ground pepper. And at the very end, add fresh thyme leaves.

4. Caramelizing the onions takes a little time, so it’s good to have them going before you prepare your other ingredients. Puff pastry is what makes this dish impressive and also a little tricky. It’s not hard to work with (it’s just dough), but you do need to be a little careful and particular.

5. Evenly distribute the caramelized onions on top of the puff pastry, leaving a 1-inch border around the edges.

6. Over the onions, drizzle the heavy cream, using the back of a spoon to gently spread it.

7. Over the top of the onions and cream, sprinkle on the grated Gruyere cheese.

8. Preheat the oven to 350 degrees Fahrenheit. Bake the tart in the oven that has been preheated for 20-25 minutes. The finished product should have a puffy and golden brown pastry. You should also see melty and bubbling cheese on top.

9. Take the tart from the oven and allow it to cool for several minutes on a wire rack.

10. Cut the tart into squares or wedges, add a sprig of thyme for garnish if you’d like (I think it looks lovely), and serve warm or at room temperature. Warm or cool, it’s a great way to use up those extra onions.

Equipment Needed

1. Oven
2. Baking sheet
3. Parchment paper
4. Rolling pin
5. Flour (for dusting surface)
6. Skillet
7. Stove or cooktop
8. Wooden spoon or spatula
9. Knife
10. Cutting board
11. Spoon (for spreading cream)
12. Cheese grater
13. Wire rack
14. Pastry brush (for egg wash, not in instructions but implied)
15. Measuring cups and spoons

FAQ

  • Can I use store-bought puff pastry?Puff pastry can be bought at the store and is perfect for this tart. It saves time in the preparation of this dish.
  • How can I prevent the onions from burning while caramelizing?Over medium-low heat, cook the onions, stirring frequently, until they are golden and tender and, more importantly, ensuring that they do not burn.
  • Can I substitute Gruyere cheese with another type?Yes, you can use Emmental cheese or Swiss cheese instead of Gruyere for a taste that’s pretty similar.
  • How do I know when the tart is fully baked?When the puff pastry is golden brown and the cheese is bubbly, the tart is done. That’s usually after about 25-30 minutes at 400°F (200°C).
  • Can this tart be made ahead of time?Certainly, it is possible to ready the tart several hours before serving. To do this, one would prep the tart and then store it. When serving time draws near, one would reheat it. In essence, one could make it many hours ahead of time, if not the day before.
  • What can I serve with this tart?This tart goes very well with salad and a nice glass of white wine. The salad can be pretty much anything, but a light, green salad with a citrus vinaigrette is a perfect match. My favorite white wine to drink with this tart is a lovely Sauvignon Blanc from New Zealand. As far as I’m concerned, you can’t go wrong with Kiwi Sauvignon Blanc.
  • Is there a vegetarian version of this tart?This recipe is inherently vegetarian, necessitating no adjustments to align with a vegetarian dietary pattern.

Substitutions and Variations

Puff pastry: If you want a new texture, try substituting a homemade pie crust or phyllo dough.
Substitute butter or a neutral oil such as canola or vegetable oil for olive oil to achieve comparable results when cooking.
Gruyère cheese: Choose Swiss cheese, Emmental, or Comté for a flavor profile similar to Gruyère.
Try half-and-half or crème fraîche in place of the heavy cream for a lighter option.
Thyme is a delicious pungent herb essential to the flavor of many Mediterranean dishes. Its fresh flavor can be captured in the simplest preparations, and its dried form, which is much more concentrated, can stand up to even slow-cooked or long-baked dishes.

Pro Tips

1. Caramelization Timing: Don’t rush the caramelization process for the onions. Cook them on medium-low heat to ensure they become sweet and golden without burning. If they’re browning too quickly, reduce the heat and add a splash of water to prevent burning.

2. Puff Pastry Handling: Keep the puff pastry cold while working with it. If it warms up too much and becomes difficult to handle, pop it back in the fridge for a few minutes to firm up.

3. Egg Wash Application: Apply the egg wash only to the edges of the pastry before baking. This will promote an even, golden-brown finish and create a visually appealing contrast with the flaky layers.

4. Cheese Variation: For a different flavor profile, try mixing Gruyere with a bit of Parmesan or Emmental cheese to add depth and nuttiness to the tart.

5. Serving Suggestions: Pair the tart with a light salad of arugula or mixed greens tossed in a lemon vinaigrette to balance the richness of the tart with a fresh, tangy side.

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Caramelized Onion Tart With Gruyere Recipe

My favorite Caramelized Onion Tart With Gruyere Recipe

Equipment Needed:

1. Oven
2. Baking sheet
3. Parchment paper
4. Rolling pin
5. Flour (for dusting surface)
6. Skillet
7. Stove or cooktop
8. Wooden spoon or spatula
9. Knife
10. Cutting board
11. Spoon (for spreading cream)
12. Cheese grater
13. Wire rack
14. Pastry brush (for egg wash, not in instructions but implied)
15. Measuring cups and spoons

Ingredients:

  • 1 sheet puff pastry, thawed
  • 2 tablespoons olive oil
  • 3 large onions, thinly sliced
  • Salt and freshly ground black pepper, to taste
  • 1 teaspoon fresh thyme leaves
  • 1/4 cup heavy cream
  • 1 cup Gruyere cheese, grated
  • 1 egg, beaten (for egg wash)

Instructions:

1. Your oven should be preheated to 400°F (200°C). A baking sheet should be lined with parchment paper.

2. On a surface lightly dusted with flour, roll out the puff pastry until it is somewhat larger than the baking sheet. Place the pastry on the baking sheet you prepared earlier.

3. In a sizable skillet, warm the olive oil over a medium flame. Toss in the sliced onions and cook, with an occasional stir, until they are fully caramelized and a gorgeous golden brown—about 25 to 30 minutes. Season with salt and contemporary ground pepper. And at the very end, add fresh thyme leaves.

4. Caramelizing the onions takes a little time, so it’s good to have them going before you prepare your other ingredients. Puff pastry is what makes this dish impressive and also a little tricky. It’s not hard to work with (it’s just dough), but you do need to be a little careful and particular.

5. Evenly distribute the caramelized onions on top of the puff pastry, leaving a 1-inch border around the edges.

6. Over the onions, drizzle the heavy cream, using the back of a spoon to gently spread it.

7. Over the top of the onions and cream, sprinkle on the grated Gruyere cheese.

8. Preheat the oven to 350 degrees Fahrenheit. Bake the tart in the oven that has been preheated for 20-25 minutes. The finished product should have a puffy and golden brown pastry. You should also see melty and bubbling cheese on top.

9. Take the tart from the oven and allow it to cool for several minutes on a wire rack.

10. Cut the tart into squares or wedges, add a sprig of thyme for garnish if you’d like (I think it looks lovely), and serve warm or at room temperature. Warm or cool, it’s a great way to use up those extra onions.