Caramelized Onion Tarts with Blue Cheese

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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!

Why you’re going to love these caramelized onion tarts:

• 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!

How to make 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.

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

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

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

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

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!

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!

How to assemble and bake these 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.

Cut each rectangle into 3 squares.

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

Brush the crust portion of the tart with the 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.

Top that with a teaspoon of caramelized onions.

Top that with a teaspoon of 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!

Do I have to use puff pastry?

Not necessarily. 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.

Where can I 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.

Do I have to use blue 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!

Do I have to use fig jam?

Again, not necessarily. But 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!

Instructions for making tarts ahead of time:

• 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.

Instructions for freezing these tarts:

• 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.

Tips for making the best puff pastry tarts:

• 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!

Other puff pastry appetizers you’ll love:

• Brussels Sprouts Puff Pastry Tart
• Prosciutto, Parmesan and Asparagus Bundles
• Pear & Gorgonzola Tarts

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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!