Savory

Caramelized Onion And Blue Cheese Tart

Name: Caramelized Onion And Blue Cheese Tart
Prep time: 30 min
Cook time: 35 min
Total time: 65 min
Yield: 6 servings
Ingredients: 1 large onion, thinly sliced; 2 tablespoons unsalted butter; 1/2 cup blue cheese, crumbled; 1 sheet puff pastry, thawed; 1/2 cup grated cheddar cheese; 1 egg, beaten; 1 teaspoon salt; 1/4 teaspoon black pepper; 1 tablespoon chopped fresh thyme; 1 tablespoon olive oil

By Clara Ingram · June 19, 2026 · Savory

Prep30 min

Cook35 min

Total65 min

Serves6

I still remember the first time I made a caramelized onion and blue cheese tart. It was a slow Sunday morning, and I was looking for a breakfast recipe that would impress my family. The combination of sweet, caramelized onions and pungent blue cheese, all wrapped up in a flaky pastry crust, was a revelation.

As a former bakery line cook turned morning-food obsessive, I've always believed that breakfast is the most underrated meal of the day. And this tart is the perfect example of why. It's easy to make, yet impressive enough to serve to guests. And the best part? It's perfect for both slow mornings and quick weekday breakfasts.

So, what makes this recipe special? For one, the caramelized onions are cooked low and slow, which brings out their natural sweetness and depth of flavor. The blue cheese adds a pungent, tangy element that balances out the sweetness of the onions. And the pastry crust is flaky and buttery, providing a perfect textural contrast to the soft onions and cheese.

This recipe is perfect for anyone who loves a savory breakfast. Whether you're a fan of sweet and savory combinations or just looking for a new breakfast idea, this tart is sure to become a favorite.

In this recipe, I'll walk you through the steps to make a delicious caramelized onion and blue cheese tart. From the initial prep work to the final presentation, I'll share my tips and tricks for getting the most out of this recipe.

Why You’ll Love This Recipe

This recipe is easy to make and requires minimal ingredients.
The combination of caramelized onions and blue cheese is a unique and delicious flavor combination.
The pastry crust is flaky and buttery, providing a perfect textural contrast to the soft onions and cheese.
This recipe is perfect for both slow mornings and quick weekday breakfasts.
The tart can be made ahead of time and refrigerated or frozen for later use.
This recipe is a great way to use up leftover onions and cheese.
The tart is perfect for serving to guests, and can be made in a variety of sizes to suit your needs.

Why This Recipe Works

The key to this recipe is the combination of flavors and textures. The caramelized onions provide a sweet and depthful element, while the blue cheese adds a pungent and tangy contrast. The pastry crust ties everything together, providing a flaky and buttery texture that complements the soft onions and cheese.

Another important aspect of this recipe is the cooking technique. By cooking the onions low and slow, we can bring out their natural sweetness and depth of flavor. This is achieved by using a low heat and a long cooking time, which allows the onions to caramelize slowly and evenly.

The blue cheese is also an important component of this recipe. Its pungent and tangy flavor helps to balance out the sweetness of the onions, creating a well-rounded and savory flavor profile.

Finally, the pastry crust is an essential part of this recipe. By using a flaky and buttery pastry, we can create a textural contrast that complements the soft onions and cheese. This is achieved by using a combination of cold butter and ice-cold water, which helps to create a flaky and tender pastry crust.

Ingredients You’ll Need

To make this recipe, you'll need a few simple ingredients. The most important components are the caramelized onions, blue cheese, and pastry crust. You'll also need some basic pantry staples, such as flour, sugar, and spices.

When shopping for ingredients, be sure to choose high-quality onions and cheese. The type of onion you use will affect the flavor and texture of the tart, so choose a sweet and flavorful variety. The blue cheese should be pungent and tangy, with a creamy texture.

1 large onion, thinly slicedChoose a sweet and flavorful variety, such as Vidalia or Maui. The onions will be caramelized, so they should be thinly sliced to ensure even cooking.
2 tablespoons unsalted butterUse high-quality, European-style butter for the best flavor. The butter will be used to caramelize the onions and add flavor to the pastry crust.
1/2 cup blue cheese, crumbledChoose a pungent and tangy variety, such as Roquefort or Gorgonzola. The blue cheese will add a strong and savory flavor to the tart.
1 sheet puff pastry, thawedUse high-quality, store-bought puff pastry for the best results. The pastry should be thawed and rolled out to a thickness of about 1/8 inch.
1/2 cup grated cheddar cheeseChoose a sharp and flavorful variety, such as extra-sharp or smoked. The cheddar cheese will add a rich and creamy element to the tart.
1 egg, beatenUse a large egg for the best results. The egg will be used to brush the pastry crust and add a golden brown color to the tart.
1 teaspoon saltUse kosher or sea salt for the best flavor. The salt will be used to season the onions and add flavor to the pastry crust.
1/4 teaspoon black pepperUse freshly ground black pepper for the best flavor. The pepper will be used to season the onions and add flavor to the pastry crust.
1 tablespoon chopped fresh thymeChoose fresh and fragrant thyme for the best flavor. The thyme will be used to add a savory and herbaceous element to the tart.
1 tablespoon olive oilUse high-quality, extra-virgin olive oil for the best flavor. The olive oil will be used to brush the pastry crust and add a rich and savory element to the tart.

Ingredients for Caramelized Onion And Blue Cheese Tart

Equipment You’ll Need

Large skillet or sauté panCutting boardChef's knifeMeasuring cups and spoonsPastry brushRolling pinInstant-read thermometer

How to Make Caramelized Onion And Blue Cheese Tart

1
Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper or a silicone mat.
2
In a large skillet or sauté pan, melt the butter over medium heat. Add the sliced onions and cook, stirring occasionally, until they are caramelized and golden brown, about 20-25 minutes.
3
Roll out the puff pastry on a lightly floured surface to a thickness of about 1/8 inch. Transfer the pastry to the prepared baking sheet.
4
In a small bowl, mix together the crumbled blue cheese, grated cheddar cheese, and chopped thyme. Sprinkle the cheese mixture evenly over the center of the pastry, leaving a 1-inch border around the edges.
5
Spread the caramelized onions over the cheese mixture, leaving a small border around the edges.
6
Brush the edges of the pastry with the beaten egg and fold the pastry up over the filling, pressing gently to seal. Use a sharp knife or pastry brush to trim any excess pastry and create a decorative edge.
7
Brush the top of the tart with the olive oil and sprinkle with salt and pepper.
8
Bake the tart for 25-30 minutes, or until the pastry is golden brown and the filling is heated through.
9
Remove the tart from the oven and let it cool for 10-15 minutes before slicing and serving.
10
To serve, slice the tart into wedges and serve warm or at room temperature. You can also refrigerate or freeze the tart for later use.

Expert Tips

To ensure that the pastry crust is flaky and buttery, keep the butter and water cold and handle the dough gently.
To caramelize the onions, cook them over medium heat, stirring occasionally, until they are golden brown and fragrant.
To add a decorative edge to the tart, use a sharp knife or pastry brush to trim any excess pastry.
To serve the tart, slice it into wedges and serve warm or at room temperature.
To freeze the tart, wrap it tightly in plastic wrap or aluminum foil and freeze for up to 2 months.
To reheat the tart, bake it in a preheated oven at 350°F (180°C) for 10-15 minutes, or until heated through.

Common Mistakes to Avoid

Not cooking the onions long enough, resulting in a tart that is not caramelized and flavorful.
Not handling the pastry dough gently, resulting in a tart that is tough and dense.
Not leaving enough space between the filling and the edges of the pastry, resulting in a tart that is messy and difficult to serve.
Not baking the tart long enough, resulting in a tart that is not golden brown and crispy.
Not letting the tart cool before slicing and serving, resulting in a tart that is messy and difficult to serve.
Not refrigerating or freezing the tart properly, resulting in a tart that is spoiled or stale.

Variations and Substitutions

Add some diced ham or bacon to the filling for a savory and meaty flavor.
Use different types of cheese, such as goat cheese or feta, for a unique and tangy flavor.
Add some chopped fresh herbs, such as parsley or rosemary, for a fresh and fragrant flavor.
Use a different type of pastry, such as shortcrust or phyllo, for a unique and flaky texture.
Add some caramelized garlic or shallots to the filling for a deep and savory flavor.
Use a different type of onion, such as red or yellow, for a unique and sweet flavor.
Add some diced bell peppers or mushrooms to the filling for a colorful and flavorful twist.

What to Serve With Caramelized Onion And Blue Cheese Tart

This tart is perfect for serving at breakfast or brunch, and can be paired with a variety of sides and drinks. Some ideas include:

A fresh fruit salad, such as strawberries or blueberries, for a sweet and refreshing contrast to the savory tart.

A green salad, such as arugula or spinach, for a light and healthy side dish.

A cup of coffee or tea, such as espresso or Earl Grey, for a rich and satisfying beverage.

A glass of juice, such as orange or grapefruit, for a tangy and refreshing drink.

Fresh fruit saladGreen saladCup of coffee or teaGlass of juiceYogurt parfaitGranola or cereal

Make-Ahead, Storage, Freezing and Reheating

To store the tart, let it cool completely on a wire rack. Then, wrap it tightly in plastic wrap or aluminum foil and refrigerate for up to 3 days or freeze for up to 2 months.

To reheat the tart, bake it in a preheated oven at 350°F (180°C) for 10-15 minutes, or until heated through.

Alternatively, you can reheat the tart in the microwave by wrapping it in a damp paper towel and heating for 20-30 seconds, or until heated through.

It's also possible to make the tart ahead of time and refrigerate or freeze it before baking. Simply assemble the tart, wrap it tightly in plastic wrap or aluminum foil, and refrigerate for up to 24 hours or freeze for up to 2 months.

Frequently Asked Questions

What type of onion is best for this recipe?

The best type of onion for this recipe is a sweet and flavorful variety, such as Vidalia or Maui. These onions will caramelize well and add a deep and savory flavor to the tart.

Can I use a different type of cheese?

Yes, you can use a different type of cheese in this recipe. Some good options include goat cheese, feta, or parmesan. Just be sure to choose a cheese that is flavorful and tangy, as it will be the main component of the tart.

How do I caramelize the onions?

To caramelize the onions, cook them over medium heat, stirring occasionally, until they are golden brown and fragrant. This should take about 20-25 minutes, depending on the type of onion and the heat level.

Can I make the tart ahead of time?

Yes, you can make the tart ahead of time. Simply assemble the tart, wrap it tightly in plastic wrap or aluminum foil, and refrigerate for up to 24 hours or freeze for up to 2 months. Then, bake the tart in a preheated oven at 400°F (200°C) for 25-30 minutes, or until golden brown and crispy.

How do I store the tart?

To store the tart, let it cool completely on a wire rack. Then, wrap it tightly in plastic wrap or aluminum foil and refrigerate for up to 3 days or freeze for up to 2 months.

Can I reheat the tart?

Yes, you can reheat the tart. Simply bake it in a preheated oven at 350°F (180°C) for 10-15 minutes, or until heated through. Alternatively, you can reheat the tart in the microwave by wrapping it in a damp paper towel and heating for 20-30 seconds, or until heated through.

What is the best way to serve the tart?

The best way to serve the tart is to slice it into wedges and serve warm or at room temperature. You can also serve it with a variety of sides and drinks, such as a fresh fruit salad, a green salad, or a cup of coffee or tea.

Can I freeze the tart?

Yes, you can freeze the tart. Simply wrap it tightly in plastic wrap or aluminum foil and freeze for up to 2 months. Then, thaw the tart overnight in the refrigerator and bake in a preheated oven at 400°F (200°C) for 25-30 minutes, or until golden brown and crispy.

The Full Recipe

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