Caramelized Onion and Balsamic Tomato Tarts.
Caramelized Onion and Balsamic Tomato Tarts…with everything bagel spice and plenty of fresh thyme. These fun tarts are the perfect summertime appetizer or light dinner. Flaky puff pastry dough topped with caramelized onions, two kinds of cheese, fresh thyme, basil, and balsamic cherry tomatoes. Once baked, the pastry dough turns golden brown and the tomatoes burst, turning sweet and delicious. You just can’t beat these easy tarts!

I know it’s Thursday and all, but my gosh I wish it was Friday. Normally the days of the week really do not matter to me at all. In general, I pretty much enjoy every day of the week. Because (for the most part), I truly love what I do. I love creating new recipes, I love styling food, and I love photographing each recipe for you all to see. And of course, my favorite part is interacting with you all through comments, emails, and Instagram. It’s the greatest job, and even just writing these sentences out has me feeling so much better. Sometimes you just have to remember the good, so you can push all the negative out. Easier said than done.
If you didn’t already guess, Tuesday was a stressful day. But today I am thankful that I have this incredibly delicious, and oh easy recipe to share. It’s a good one that I have been dying to share for weeks now.
Typically, I get ideas for new seasonal recipes weeks and weeks before the season actually starts. So by the time I’m ready to share the recipe with you all, I’m usually overly excited. I mean, I’ve been keeping the recipe all to myself, I’m dying to share it!
The good news is that summer is so close. Which means tomatoes have started to arrive. Which means it’s tomato tart season!
YESS!

What I love about tart recipes is that they are truly the easiest. I usually use my favorite store-bought puff pastry and then just layer on my toppings. Puff pastry is one of those store-bought items that I find so much easier to just pick up at the store versus making it at home. I know some might argue this, but I live by store-bought puff pastry. It’s one of my favorite ingredients to use to whip up quick and delicious recipes.
Bottom line here? Keep your freezer stocked with puff pastry. OK? Great. Moving on.

To start, you’ll need to caramelize some onions, which is really simple. Just cook up some onions along with the tiniest amount of honey until the onions turn deep golden in color. The honey helps to caramelize the onion faster, giving them a rich color and flavor. While caramelizing the onions is an additional step, it’s so worth it. The caramelized onions make this tart.
While the onions are cooking away, start preparing the pastry. All you need to do is roll the pastry out and cut it into 4 squares. Very easy.
Now, toss those sweet and juicy cherry tomatoes with some balsamic vinegar, and fresh basil.
Layer the onions over the pastry squares, add a mix of cheddar and Havarti cheese, and then pile on the tomatoes. You may worry that there are too many tomatoes for the amount of dough, but don’t stress. The tomatoes burst and break down in the oven. They are so delicious!
Finish each pastry square off with a sprinkle of everything bagel spice. My favorite seasoning blend to mix with summer tomatoes. And then bake!

As this bakes, the tomatoes slowly roast, the cheese melts, and the pastries become flaky. SO GOOD.
And…your kitchen will indeed smell amazing! Like the flavors of summer…again, just SO GOOD.
Make these tarts as an easy dinner to pair with a simple side salad, or serve them up as an appetizer for your next gathering. Either way, these are going to be loved by all. My hope is that they’ll become a staple in your kitchen for the next few months.

If you make these Caramelized Onion and Balsamic Tomato Tarts, be sure to leave a comment and/or give this recipe a rating! Above all, I love to hear from you guys and always do my best to respond to each and every comment. And of course, if you do make this recipe, don’t forget to tag me on Instagram! Looking through the photos of recipes you all have made is my favorite!

Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Caramelized Onion and Balsamic Tomato Tarts
Flaky puff pastry dough topped with caramelized onions, 2 kinds of cheese, thyme, basil, and balsamic cherry tomatoes. Once baked, the dough turns golden brown and the tomatoes burst, turning sweet & delicious!
Ingredients
- 2 tablespoons extra virgin olive oil
- 1 yellow onion, thinly sliced
- 1 teaspoon honey
- kosher salt and black pepper
- 1 garlic clove, minced or grated
- 2 tablespoon fresh thyme leaves, plus more for serving
- 1 cup shredded sharp cheddar cheese
- 1/2 cup shredded Havarti cheese
- 1 sheet frozen puff pastry, thawed
- 2 cups cherry tomatoes
- 2 tablespoons balsamic vinegar
- 1/4 cup fresh basil, chopped
- 1 pinch crushed red pepper flakes
- 1 egg, beaten
- everything bagel spice, for sprinkling
- fresh chopped chives
Instructions
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1. Preheat the oven to 425 degrees F. Line a baking sheet with parchment paper.
2. Heat 1 tablespoon olive oil in a large skillet over medium-high heat. When the oil shimmers, add the onions and honey and cook 5 minutes, stirring occasionally until softened. Season with salt and pepper and continue cooking another 5-10 minutes or until the onions are golden and caramelized. Add the garlic, and thyme, cook another minute. Remove from the heat.
3. In a bowl, combine the remaining 1 tablespoon olive oil, the tomatoes, balsamic vinegar, basil, crushed red pepper, and a pinch each of salt and pepper.
4. Lay the pastry sheet flat on a clean, floured surface. Gently roll the sheets out to stretch slightly. Cut each sheet into 4 squares and place onto the prepared baking sheet. Evenly top each square with onions, leaving a 1/4 inch border. Top with both kinds of cheese and then mound the tomatoes over the cheese, pressing them into the cheese to adhere slightly (see above photo).
5. Fold the edges of the pastry inward to enclose the tomatoes. Brush the edges of the pastry with beaten egg and sprinkle with everything spice. Transfer to the oven and bake for 20-25 minutes or until the pastry is golden and the tomatoes burst. Top with fresh thyme and chives.
Recipe Notes
Calories based on being served as a main

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Is this a “serve immediately” type of recipe? I’d love to try it but my husbands hours are very unpredictable and I wouldn’t be able to make it as he walks in the door. Will it hold?
Hi there! I personally love these tarts best warm, BUT they are delicious room temp too. If you don’t mind room temp food, then I say go for it. Flavors are still delicious! Please let me know if you have any other questions. I hope you love this recipe! Thank you! xTieghan
I tried making my own puff pastry a couple of times…..UGH!!
It came out good, but the work involved in it is too much for me.
I’m very happy just buying boxes of puff pastry and keeping them in my freezer.
I’m happy that I can say that I did try it though.
Tomatoes are so big in my home, LOVE them!!
This is a delicious looking tart to share with friends.
I would also try sesame seeds as another choice along with the everything bagel spice blend.
Some of my friends aren’t into the everything bagel spice blend.
More for me bwahahaha!!
Have a nice day Tieghan!
Yes it is amazing that you can say you tried, Dalila! I am so glad you like this tarts and I hope they turn out amazing for you! xTieghan
what an interesting idea this one is, I’m going to make a version of this soon!
I hope you love it! Thank you Ruth! xTieghan
Question
One “sheet” of puff pastry? Or one package maybe?
One sheet would be just about the thickness of a sheet of tissue paper and wouldn’t puff much, or would it?
This sounds delicious and I would do the full three quarters of an hour for caramelizing the onions.
Hi! 2 sheets of pastry are in 1 box of puff pastry. You only need 1 sheet of pastry for this recipe. Does this make sense? Please let me know if you have any other questions. I hope you love this recipe! Thank you! xTieghan
Dear Theighan, Thanks for this great recipe. When i try to make tomato tart i always end up with a soggy tart bottom. How do you prevent that in your recipe? Thanks!
Hi there! Just don’t overcrowd the pastry with tomatoes and you should not have a soggy crust. Using smaller pastry squares helps keep everything crisp. Please let me know if you have any other questions. I hope you love this recipe! Thank you! xTieghan
great dish, and really creatively rustic too, it deserves a good wine to pair with, thank you!
Thank you Sabrina! xTieghan
Oooh, I recently found GF puff pastry; I’m going to make these as soon as my tomatoes ripen!
So Perfect! I hope you love this recipe, Kate! xTieghan
I loved this recipe, I always go back to your web site
Thank you so much Caroline! I am so glad you enjoyed this! xTieghan
My comment has nothing to do with this recipe. I printed out one of your recipes (the Greek Watermelon Feta Salad with Basil Vinaigrette) this morning. Then this afternoon I decided I wanted to save the recipe on Pinterest. I looked at my printed recipe and Half Baked Harvest is nowhere on it! I had already deleted your email and my mind was a complete blank on remembering Half Baked Harvest to try and find the recipe. I searched my deleted emails and found it. I just wanted you to know that you need to add Half Baked Harvest to your recipes in the print stage, so you get credit for them and in case someone wants to know who the recipe is from. Looking forward to making the watermelon feta salad. It sounds delish!!!
Thank you so much Donna! I will definitely add that to the print page! xTieghan
Delicious recipe! It was a great way to use ingredients that I normally stock in my kitchen. To keep things simple, I used dried basil, thyme, and chives since I had them on hand. The dried herbs worked out great. Although, I feel like using fresh basil will make the tarts even more flavorful so I’ll try that next time.
I hope you love it even more, Gloria! Thank you so much! xTieghan
I love your page, I love this recipe even though I have not tried it yet. I can tell that it is going to be awesome. I am just starting out with a blog and I get lots of inspiration looking at well put together pages like this one.
Thank you so much Judith! I hope you try this recipe and it turns out well for you! Also, hope your blog is doing good, that is so amazing! xTieghan
These are THE BOMB!!!! so easy , so tasty and amazing. I will definitely make it a point to keep puff pastry in the freezer from now on. I 1st made your “Caprese Pesto Pasta Bake” a couple of days ago (FABULOUS by the way) and had the leftovers in the fridge. I came home from work yesterday to find my 19 year old son heating the leftover pasta ON TOP of these tarts and he gobbled it up – “this is AWESOME!’ he says. Chicken Souvlaki Bowls for dinner tonight!! thank you so much for your incredible recipes.
Thank you so much Meagan! I am so glad these tarts turned out amazing for you! xTieghan
Prettiest tarts for summer! There’s nothing better than caramelized onions and tomatoes! 🙂
Thank you so much Laura! xTieghan
I made the for dinner tonight, everyone liked them (including a 3.5 yo and The baby that just turned 1!)
I crowded the pan a bit and a few tomatoes fell off but that was the only thing! I didn’t even substitute anything, I had all the ingredients ! Amazing lol!
Thank you so much Linda! xTieghan
I made these when my 15 year old had 2 friends over, everyone loved them! My 13 year old, my husband, my mother, we all really liked this recipe! It took a while for me to get everything cooked, I made brussel sprouts as well.
AMAZING! Thank you so much for trying this, Amanda! So glad you all loved this recipe! xTieghan
I made this recipe more caprese style (ricotta smeared on the bottom and fresh mozzarella for cheeses) and added an arugula salad for the top. The recipe was great! I would recommend halving the tomatoes because they shoot out very hot liquid after coming out of the oven! Overall though, super delicious and light! Perfect for summer
Thank you so much Skyler!! So happy to hear that you loved this recipe! xTieghan
This is the perfect summer dish! Light, flavorful, filling and absolutely beautiful! (I added arugula to the top of mine and love, love, loved it!)
Love to hear that Ali! Thank you so much! xTieghan
I plan to make this as an appetizer for 10. I’m using pre-rolled puff pastry sheets.
What is the approximate dimension of your puff pastry squares? I think I’ll use 2 sheets.
These look so good….love all your recipes.
Hey Sandra! I am sorry but I don’t have the dimensions. If you are doubling the recipe, 2 sheets will be great! Please let me know if you have any other questions. I hope you love this recipe! Thank you! xTieghan
Just made these and they are delicious! Super quick and easy, perfect to make for company.
Agreed! I am so glad this turned out so well for you Karina! Thank you! xTieghan
Could you make and bake these and then freeze them and warm them up to use later?
Hi! Yes, that works very well. I would rewarm them from frozen in the oven for 15-20 minutes. Please let me know if you have any other questions. I hope you love this recipe! Thank you! xTieghan
This recipe looks amazing!
Could you make it hours ahead ready to put in the oven or will the pastry go soggy?
Hi!! Yes, that works really well! The pastry should hold up just fine for a few hours in the fridge. Please let me know if you have any other questions. I hope you love this recipe! Thank you!! xTieghan
I made these last night for an appetizer and they were so delicious! Instead of havarti I used provolone and ADD FRESH BURRATA!! to the top after they come out of the oven.. absolute game changer. Most delicious thing I’ve made in a really long time (maybe ever?)
Yes!! So happy to hear that Aly! Thank you so much for trying this one! xTieghan
This was so delicious! My daughter loved it – she called it fancy pizza.
Ooo lala haha! I am glad you both enjoyed this recipe, Amy! Thank you for trying it! xTieghan
Just made this – it was incredible!! Couldn’t wait to try it…burned the top of my mouth…but so good.
Thank you for such delicious and beautiful recipes!! I love cooking from your recipes.
Oh no!! I hope you are okay! I am SO glad you loved this recipe though, Arnaz!! Thank you so much for trying it! xTieghan
So so good!!!
Thank you so much Nadia! xTieghan
Omg deliciousness. Made it with edible flowers for the first go around (photo on IG @wander_work_repeat). Will make tomorrow and serve with a fried egg on top.
Love that! Thank you so much Meredith! xTieghan
This one is a keeper! Loved everything about it — next time I think I will double up on the carmelized onion, which makes everything delicious. I discovered I had grape (not cherry) tomatoes, but it turned out great anyway. The Everything spice is a nice finish. I love your recipes!
Thank you so much Jane! I am really glad you enjoyed this one!! xTieghan
I have made these a few times. My mom is crazy for them. They freeze so well too. Deliciousness. My mouth waters just writing this.
Thank you so much Laurie! xTieghan
I love every recipe of yours that I try – and this one is no exception! This recipe is SO simple and so good. The fresh thyme and everything bagel seasoning really takes this to the next level. Super simple and we all loved it. My Dad wasn’t expecting a lot from these and devoured his saying “this is really good, really.” Again, delicious and it was made even better with how easy and quick it was to make (and barely got any dishes dirty in the process!).
Amazing! I am really glad this turned out so well for you all, Melissa! Thank you! xTieghan
Delicious!!
Thank you Ineke! xTieghan
Mine didn’t come out nearly as beautiful as Tieghan’s (nothing ever does!) but boy, did these taste delicious! I didn’t have havarti so I only used cheddar, and I didn’t feel like it was lacking anything. The onion mixture with the fresh thyme and honey is so delicious, I will definitely use it in other recipes.
Tieghan, do you think you’d be able to prepare these ahead of time and bake whenever you’d like them? Or does that get complicated with the puff pastry? Thanks!
Hey Blayre,
Thanks so much for giving the recipe a try, I am so glad it was enjoyed! You can make ahead of time:) Happy New Year! xTieghan
Another delicious recipe of yours was added to our dinner rotation last night — thank you Tieghan!
I addded shredded chicken to make it a main dish and everyone loved it.
Hey Kelly,
I am delighted you enjoyed the recipe, thanks so much for giving it a try! xTieghan
These tarts were the hit of our family birthday brunch! I made the onions the night before, and the tomato mixture in a separate bag. Let everything come to room temp &assembled/baked the day of. So, so wonderful! TY! They were gone too fast to photograph!
Hey Janice,
Thanks so much for making this recipe, I am thrilled that it was enjoyed!! xTieghan
Simply amazing – been meaning to rate as I’ve already made these 5 times. My family keeps asking for them and now they are requested for holidays! A true winner, thank you!!!
Hey Katie,
Happy Monday! I am so glad this recipe was enjoyed, thanks a bunch for making it! xTieghan