These TikTok-inspired upside down onion tarts, with their irresistible crunch and savory flavors, are the perfect party snack.
They’re buttery, crispy, and flaky and have the deliciousness of caramelized onion and Gruyere cheese packed in a teeny, bite-sized format that makes them perfect for your house parties! Finish up with a drizzle of habanero hot honey over them for extra yumminess!
The golden brown crispiness and the sweet and savory caramelized onion, teamed up with the cheese make these an irresistible snack that everyone will love.
They’ve become my recent favorite- I’ve paired them with my Turkish cheese rolls and Tajin nuts, and they were a total hit! This quick and easy-to-make appetizer truly has my heart!
Quick Look: Upside Down Onion Tarts
- 🔪 Prep time: 10 minutes.
- ⏲️ Cook time: 20–25 minutes.
- 👪 Servings: 4.
- 📋 Main ingredients: Puff pastry, sweet onions, Gruyère cheese, honey, balsamic vinegar, thyme, chili flakes.
- ♨️ Cooking method: Layer → top with puff pastry → bake → invert and serve.
- ⭐ Difficulty: Easy.
- 🥣 Serving ideas: Serve as an appetizer with a charcuterie board, alongside marinated feta and olives or crispy fried stuffed olives.
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What's So Great About the Recipe?
- They're incredibly easy to make- you'll just need a few minutes of prep and they'll be ready in under 30 minutes.
- Like my spinach feta crisps, they're perfect to make for a party you're hosting.
Recipe Ingredients
Puff pastry: Puff pastry serves as the base for these delicious onion tarts. You should be able to find them in the frozen section of your supermarket.
White onion: White onions, when caramelized, bring an insanely delicious savory and umami flavor to the upside-down tarts.
Balsamic vinegar: A dash of balsamic vinegar or balsamic glaze can bring some more depth of flavor and complexity to these puff pastry tarts.
Honey: I used a light drizzle of my homemade hot honey to jazz up the flavors in these tarts. You can also use hot honey butter if you want to.
Gruyere cheese: Gruyere cheese, teamed up with the caramelized onions is what brings the perfect French onion flavor into these little tarts.
Egg: You’ll also need an egg to make a simple egg wash to coat the upside-down tarts.
Thyme: The fragrant thyme brings a nice earthy and aromatic flavor to the tarts.
Chili flakes: I used red chili flakes to season the tarts, but you can totally choose to keep it simple with just salt and pepper. Sometimes, I also use my homemade garlic bread seasoning when I have it at hand.
See recipe card for quantities.
Substitutions & Variations
- You can choose to use fresh or dried thyme- whatever you have at hand.
- If you’re looking to make a vegetarian version of these upside down onion tarts, skip the egg wash and just brush a little olive oil onto the puff pastry before you pop them in the oven. I love using my lemon infused olive oil when I can!
- White onions are the best choice for this recipe, but if you’re not able to find them, red onions can work too.
- Sprinkle some homemade herb salt or garlic parsley salt over the tarts before serving for an extra flavor boost.
How to Make Upside Down Onion Tarts
Step 1: Preheat oven to 400°F. Meanwhile, get the sliced onions and cheese ready and cut the puff pastry into rectangles.
Step 2: On a large baking sheet lined with parchment paper, add a teaspoon of balsamic vinegar, some honey, and a sprig of thyme, and sprinkle some chili flakes in different sections.
Step 3: Place a slice of onion on top of the puddle with the Gruyere cheese slices.
Step 4: Top with puff pastry and brush with beaten egg.
Step 5: Bake until golden brown and crispy.
Step 6: Carefully lift each tart, flip over and bake again for 2-3 minutes.
💭Top Tip
You can also flatten the puff pastry if you want to. Press the pastry around the edges using a spatula before you bake them.
Tips & Tricks to Nail the Recipe
- Remember to start off with thawed puff pastry. This will ensure that the pastry is cooked to perfection, and is easier to work with as well.
- You can also experiment with different types of ‘fillings’ for these upside down tarts. Think mushrooms, roasted garlic, bell peppers and even tomato garlic confit- they're all splendid options worth trying out.
- Another great idea is to use shallots instead of onions, or even use some other kinds of onions of your choice- I love using my homemade balsamic pickled onions!
- To add some extra flavor to these delicious puff pastry tarts, you can sprinkle some beef or mushroom bouillon powder onto the onion slices before you place the pastry on the top!
- Remember to allow them to cool down for a few minutes and run a knife under the tarts to remove them easily.
How to Serve Upside Down Onion Tarts
This upside-down onion tart is a show-stopping dish that’s sure, but you might want to take it to the next level by teaming it up with a nice dip too!
I love the idea of pairing these with a creamy condiment- maybe jalapeno honey mustard or roasted garlic sauce. I also love drizzling some more hot honey and balsamic glaze over the top, right before serving! I think these tarts would also taste fantastic with some spicy tomato jam.
Troubleshooting & FAQs
If you’re not able to find Gruyere cheese, you can choose to use some creamy Brie or goat cheese instead! Cream cheese can also work in a pinch!
I would highly recommend using flaky puff pastry for this recipe. While you can try this recipe with any other kind of pastry too, you won’t be able to enjoy the same crispiness and layers of flaky goodness as you would with the traditional puff pastry.
You can store your leftover caramelized onion tarts in an airtight container and then refrigerate them for up to 2 days.
You can reheat these onion tarts in the oven. I wouldn’t recommend microwaving them, as it can really cause the puff pastry to become soggy.
More Easy Snacks & Appetizers
Looking for other recipes like this? Try these:
If you tried these upside down onion tarts or any other recipe on my website, please leave a 🌟 star rating and let me know how it went in the 📝 comments below. Thanks for visiting!
Upside Down Onion Tarts
Ingredients
- 1 sheet puff pastry thawed
- 3 sweet onion thinly sliced
- 3 tablespoon honey
- 1 tablespoon balsamic vinegar
- 1 teaspoon chili flakes
- Fresh thyme leaves, salt, and black pepper to taste
- 18 pcs thinly sliced gruyere cheese or as needed
- 1 egg beaten
Instructions
- Preheat oven at 400°F. Meanwhile, get the sliced onions and cheese ready and cut the puff pastry into rectangles.
- In a large baking sheet lined with parchment paper, add a teaspoon of balsamic vinegar, some honey, a sprig of thyme and sprinkle some chili flakes in different sections.
- Place a slice of onion on top of the puddle and then with the Gruyere cheese slices.
- Top with puff pastry and brush with beaten egg.
- Bake for 20 to 25 minutes until the onions caramelize and the top is golden brown.
Notes
- Remember to start off with thawed puff pastry. This will ensure that the pastry is cooked to perfection, and is easier to work with as well.
- To add some extra flavor to these delicious puff pastry tarts, you can sprinkle some beef or mushroom bouillon powder onto the onion slices before you place the pastry on the top!
- Remember to allow them to cool down for a few minutes and run a knife under the tarts to remove them easily.
