This post contains affiliate links.
Get ready to wow your friends and family with this upside down onion tart! Caramelized onions, creamy brie, and fresh thyme come together in a golden, flaky puff pastry that’s almost too pretty to eat (almost). With dozens of 5-star reviews, this one’s guaranteed to make you look like a pastry pro.
save this recipe!The Only Appetizer You Need
Upside-down tarts are having their moment, and I am fully here for it. From fruity to savory, the concept couldn’t be simpler: assemble upside down, bake, and flip.
This savory spin involves buttery puff pastry layered with balsamic-glazed onions, fresh thyme, and creamy brie—all caramelized to perfection. Once baked, flip your upside-down onion tart over to reveal a drool-worthy, golden masterpiece that looks as pretty as it is delicious.
Reader rating
“Yum. Loved making and eating these delights. Will definitely be doing them again.” —Sue-Ellen Green
Let’s Talk Ingredients
Can you believe this fancy-looking recipe has less than ten ingredients?! This is just an overview—jump to the recipe card for exact measurements.
- Puff Pastry: Puff pastry serves as the base for our tart, providing a light, flaky, buttery texture that complements the caramelized onions and brie.
- Glaze: The sweet, tangy balsamic glaze adds depth, complexity, and a hint of acidity. I like using glaze (instead of vinegar), which is thicker and sweeter. We’ll also add a drizzle of olive oil to prevent sticking.
- Onions: The thinly sliced onions become wonderfully caramelized during baking, adding a sweet and savory element to the tart.
- Brie: Rich and creamy brie cheese melts perfectly, creating a lusciously gooey layer that complements the caramelized onions.
- Seasonings: We’ll use salt, pepper, and fresh thyme leaves to bring a balanced, earthy note with a slight kick. You could also try rosemary!
- Egg: Finally, we’ll brush the pastry with a beaten egg, giving it a beautiful golden color and a glossy finish after baking.
Buying Tips!
Puff pastry can usually be found in the frozen section of most grocery stores. When choosing puff pastry, look for one made with real butter for an extra flaky, rich flavor.
As for balsamic glaze, you’ll typically find it in the condiment aisle or specialty food stores. For the best flavor, check for DOP-certified (Denominazione di Origine Protetta) balsamic vinegar from Modena, Italy, which is known for its superior quality.
Making Onion Tarts Is Simple
Despite looking complicated, these upside-down onion tarts are ridiculously easy to make (jump to the recipe card for the full printable instructions).
Step 1: Prep The Pastry
Cut the puff pastry into eight equal squares, which will serve as the individual bases for your onion tarts. Preheat the oven so it’s ready to go when you are!
Step 2: Layer The Tarts
Drizzle small puddles of olive oil and balsamic glaze on a large baking sheet. Place an onion slice on each puddle, then sprinkle with thyme, salt, and pepper, and top with brie triangles.
Step 3: Cover With Pastry
Cover the onion slices with puff pastry squares, making sure the cheese and onions are completely covered, then brush the tops with your egg wash.
Step 4: Bake The Tarts
Bake the tarts until golden brown and cooked through. Cool briefly before removing from parchment.
Flavor Switches
- Change Up The Onions: Experiment with different types of onions to switch up the flavor profile. Sweet onions, like Vidalia or red onions, work well here, but you can also try shallots or leeks for a unique twist.
- Different Cheese: If you prefer a stronger cheese flavor, you can use a different type of cheese. Goat cheese and blue cheese both add a tangy and distinct taste to these onion tarts.
- Optional Add-Ins: To enhance the flavor, try adding ingredients like sliced mushrooms, roasted garlic, or even a drizzle of honey.
For The Love Of Onions
Upside Down Onion Tart With Brie
Ingredients
- 1 17.3 oz package puff pastry, 2 sheets, 490 g
- 4 Tbsp olive oil, 60 mL
- 4 Tbsp balsamic glaze, 60 mL
- 8 sprigs fresh thyme
- 8 pinches salt and pepper
- 2 medium onions, peeled and thinly sliced
- 1 wheel brie cheese, cut into 8 triangles
- 1 large egg
Instructions
- Prep: If frozen, let the puff pastry thaw on the counter until soft and pliable. Once thawed, cut into 8 equal squares. Preheat the oven to 400°F (204°C). Slice the onion and remove the thyme leaves from their stems.
- Layer: Line a large baking sheet with parchment paper. Drizzle oil equally around the baking sheet to make 8 little puddles. Drizzle on balsamic. Top each with an onion slice. Sprinkle on thyme leaves, salt, and pepper. Top with a slice of brie.
- Cover: Top each mound with the puff pastry, pressing the edges down to completely cover the cheese and onion. Whisk the egg together, then brush it over the pastry.
- Bake: Bake on the middle rack for 15 minutes until golden brown and cooked through. Let cool on the baking sheet for a few minutes before trying to remove from the parchment.
Notes
Nutrition
Nutrition information calculated by Sarah Bond, degreed nutritionist.
did you make this?Leave a comment below and tag @liveeatlearn on social media! I love seeing what you’ve made!
Hello! Thank you so much for this delicious and super easy recipe! I send it to my daughter that is at university in Prince eduard island cause she will adore it 😍 question.. can you freeze it?
I haven’t tried freezing this recipe so I can’t say for sure! If you’re going to, I would freeze it before baking 😀
Yum loved making and eating these delights. Will definitely be doing them again.
Can a Silpat mat work as well as the parchment paper? I find parchment to be a bit of a pain.
Yes, that would work!
Is balsamic glaze the same thing as balsamic vinegar, or do I need to do something to the vinegar to make it a glaze?
Balsamic glaze is more concentrated! You can either buy it or simmer balsamic on the stove uncovered until it’s thick and syrupy 🙂
Loved this! I tried this recipe with Boursin cheese since it was the only cheese I had. It was creamy and delicious! I plan to get brie cheese and make this again!
This is one of those recipes that can impress without investing too much time.
Oh my gosh, it sounds so delicious with that cheese added! Thanks so much for dropping back in to let us know how it went. Happy eating!