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Caramelized Onion Tarts with Blue Cheese

These SUPER easy caramelized onion tarts are loaded with sweet fig jam, tangy blue cheese and flaky puff pastry crust baked to perfection, then drizzled with honey!

Overhead shot of parchment paper with caramelized onion puff pastry tarts on top of it


 

You’ll Love These

  • They’re unexpected yet classic. The flavor combo of caramelized onion and blue cheese is a classic one but combining them on top of a flaky puff pastry is likely something your friends haven’t tried before – and they are going to LOVE it!
  • They’re a really fun recipe to make when you’ve got a free afternoon to mess around in the kitchen. I like to invite friends over, open a bottle of wine and spend the afternoon chatting in the kitchen – I find it’s more fun when you get friends involved.
  • They’re the perfect handheld appetizer for your next party. They taste great fresh and warm from the oven, or they taste amazing at room temp too. Which makes them the perfect treat for your next get together!
Close up shot of a tower of caramelized onion tarts being drizzled with honey

Caramelized Onions

Grab a magazine (or who am I kidding, your phone) and a glass of wine and plop yourself on a stool in front of the stove. It’s going to take 60 minutes to caramelize these onions, but it’s SERIOUSLY worth every single second – trust me.

Halve 2.5 pounds of onions.

Brown cutting board with halved onions on it

Thinly slice the onions about an 1/8″ thick.

Brown cutting board filled with sliced onion

Heat olive and butter over medium heat in a heavy bottom pan. Add sliced onions.

Large white pan filled with sliced onions

You’ll be cooking these onions for a total of 60 minutes and stirring them every 5 minutes. I like to use a wooden spoon or spatula for stirring these babies.

After about 10 minutes of cooking, add a large pinch of salt.

Large white pan with sliced onions with salt being added

This is what your onions will look like after about 30 minutes.

Large white pan filled with caramelizing onions

After about 40 minutes of cooking, add a teaspoon of sugar.

Large white pan filled with caramelized onions with sugar being added

After you’ve cooked the onions for a full 60 minutes, pour in wine to deglaze the bottom of the pot. Be sure to scrape all the yummy bits off the bottom of the pan!

Caramelized onions with white wine being poured over them

That’s it! Caramelized onions are easy peasy!

When the caramelized onions are almost done, preheat your oven to 400 degrees and get to work assembling those tarts!

Assembling Tarts

Unroll both sheets of puff pastry. Cut along the seams of each sheet of puff pastry, creating 6 rectangles total out of the two sheets of puff pastry.

Three rectangles of puff pastry on a marble counter top

Cut each rectangle into 3 squares.

Several squares of puff pastry on a marble counter top

Use a sharp knife to score a crust about a half inch wide around the edge of each square.

A parchment lined baking sheet with squares of puff pastry on it

Brush the crust portion of the tart with the egg wash.

Parchment lined baking sheet with squares of puff pastry brushed with egg wash

Spread a teaspoon of fig jam (this is my fave brand) in the center of each tart. A cookie scoop is helpful here to make sure each tart gets the same amount of jam.

Parchment lined baking sheet with squares of puff pastry on it with fig jam being added

Top that with a teaspoon of caramelized onions.

Parchment lined baking sheet with squares of puff pastry on it with caramelized onions being added

Top that with a teaspoon of blue cheese.

Parchment lined baking sheet with squares of puff pastry on it being topped with blue cheese

Bake tarts for 18-20 minutes or until the crust starts to get dark golden brown. Add a few thyme leaves to each caramelized onion tart and drizzle them with honey. Serve warm or at room temp and enjoy!

Parchment lined baking sheet filled with freshly baked caramelized onion tarts

Pastry Substitutes

You could use pie crust or even crescent rolls. However, puff pastry has the perfect buttery flakiness needed for this dish, so it’s best to stick to the recipe here and use traditional puff pastry sheets. Thaw them in the fridge overnight so they are easy to unroll and cut.

Find Puff Pastry

You’ll typically find puff pastry in the freezer section of your grocery store near the dessert items. Pepperidge Farm is my favorite reasonably priced brand that can be found at most grocery stores.

Close up shot of a caramelized onion tart drizzled with honey

Cheese

You could use Gorgonzola or Roquefort instead as they both have a rich, tangy flavor similar to blue cheese. But luckily, blue cheese is very popular and super easy to find so you shouldn’t have to spend too much time hunting it down!

Jam

To achieve the same flavor profile, it is ideal to use fig jam. Any sweet fruit preserve will work, however the flavors of fig work very well with blue cheese and honey and lucky for you, most grocery stores carry fig jam or fig preserves!

Overhead shot of a white counter top with caramelized onion tarts on it

Make Ahead

  • You could make the caramelized onions up to a week in advance and store them in an airtight container in the fridge. Before assembling, let them sit on the counter for one hour to come to room temp.
  • Assemble tarts on parchment lined baking sheet. Cover with saran wrap and refrigerate for up to 24 hours before baking.
  • When you’re ready to bake, remove from fridge (remove saran wrap) and let tarts sit on the counter for about 5-10 minutes.
  • Then bake according to recipe instructions, garnish with thyme and drizzle with honey.

Freezing

  • Assemble the tarts, freeze them on a parchment lined baking sheet and then transfer them to an airtight container and freeze for up to two months.
  • The day before baking, allow the tarts to thaw in the fridge overnight on a parchment lined baking sheet.
  • When you’re ready to bake, remove tarts from fridge and let them sit out on the counter for 5-10 minutes.
  • Then bake, add fresh thyme and drizzle with honey.
Close up shot of a white counter top with caramelized onion tarts on it

Tips

  • If you’re obsessed with that tangy blue cheese flavor like I am, reserve a couple tablespoons to top the tarts after they’ve baked. This burst of fresh blue cheese is really going to amp up the flavor and I LOVE LOVE LOVE it.
  • Puff pastry is the best dough for this recipe. Crescent rolls or even pie crust can be used as substitutes, but puff pastry is going to give you the best result for this recipe.
  • When you’re caramelizing the onions, don’t worry if the bottom of the pan gets lots of dark brown bits stuck to the bottom. At the end of the 60 minutes, you’ll be deglazing the pan with white wine and scraping all those yummy bits off the bottom.
  • Puff pastry is pretty forgiving, but it needs to be kept cold in order to rise properly when baked. So you definitely don’t want to let these babies sit out on your counter for too long or get anywhere near room temp before you bake them. Work quickly for best results!

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Caramelized Onion & Blue Cheese Puff Pastry Tarts

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5 from 4 reviews

These tarts are as elegant as they are delicious. Caramelized onions combine with tangy blue cheese and sweet fig jam to deliver a palete pleasing flavor your friends and family will love!

  • Author: Kylie
  • Prep Time: 20 minutes
  • Cook Time: 1 hour + 20 minutes
  • Total Time: 1 hour 40 minutes
  • Yield: 18 tarts 1x
  • Category: Appetizer
  • Method: Baking
  • Cuisine: American

Ingredients

Units Scale
  • 1 (17.3 oz.) package puff pastry, thawed in the fridge overnight
  • 2.5 pounds white or yellow onions, halved, then sliced 1/8″ thick
  • 1 tablespoon butter
  • 1 tablespoon olive oil
  • 1 teaspoon granulated sugar
  • 1 tablespoon dry white wine
  • Kosher salt
  • 1 egg, beaten
  • 9 oz. fig jam
  • 5 oz. crumbled blue cheese
  • 2 teaspoons fresh thyme leaves
  • honey for drizzling

Instructions

  1. Heat butter and oil in a large pot over medium heat. Add onions and stir to coat in oil. You will cook the onions for 60 minutes total, stirring every 4-5 minutes or so.
  2. After they’ve cooked for 10 minutes add a pinch of salt.
  3. After they’ve cooked for 30 minutes, turn the heat to medium low. Don’t forget to keep stirring!
  4. After they’ve cooked for 40 minutes add a teaspoon of sugar. Be sure to keep stirring them every 4-5 minutes so they cook evenly.
  5. After they’ve finished cooking for 60 minutes and are a gorgeous dark brown color, pour in the wine and deglaze the pan (scrape all the bits off the bottom) and set aside.
  6. When the onions are nearing the end of the caramelizing process, preheat oven to 400 degrees.
  7. Unroll both sheets of puff pastry and cut along the seams of each sheet, creating 6 rectangles total.
  8. Cut each rectangle into 3 squares. Use a knife to score a half inch crust around the outside of each tart.
  9. Transfer tarts to (2) parchment lined baking sheets. Arrange tarts on the two baking sheets about an inch apart. 
  10. Brush the crust portion of the tart with the egg wash.
  11. Spread a teaspoon of fig jam in the center of each tart.
  12. Top that with a teaspoon of caramelized onions.
  13. Top that with a teaspoon of blue cheese. 
  14. Bake tarts for 18-20 minutes or until the crust is dark golden brown.
  15. Remove tarts from the oven, sprinkle each with a few leaves of thyme and drizzle with honey.
  16. Serve warm or at room temp and enjoy!

Notes

If you’re obsessed with that tangy blue cheese flavor like I am, reserve a couple tablespoons to top the tarts after they’ve baked. This burst of fresh blue cheese is really going to amp up the flavor and I LOVE LOVE LOVE it.

Puff pastry is the best dough for this recipe. Crescent rolls or even pie crust can be used as substitutes, but puff pastry is going to give you the best result for this recipe.

When you’re caramelizing the onions, don’t worry if the bottom of the pan gets lots of dark brown bits stuck to the bottom. At the end of the 60 minutes, you’ll be deglazing the pan with white wine and scraping all those yummy bits off the bottom.

Puff pastry is pretty forgiving, but it needs to be kept cold in order to rise properly when baked. So you definitely don’t want to let these babies sit out on your counter for too long or get anywhere near room temp before you bake them. Work quickly for best results!

Nutrition

  • Serving Size: 1/32 of tart
  • Calories: 138
  • Sugar: 4.4 g
  • Sodium: 95.9 mg
  • Fat: 8.2 g
  • Carbohydrates: 14 g
  • Fiber: 0.6 g
  • Protein: 2.6 g
  • Cholesterol: 9.8 mg

This post was originally published in November 2018. It was updated in August of 2019 to include step-by-step instructions, process shots and tips for making the best puff pastry tarts every single time!

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