These Caramelized Onion Brie Bites are an irresistible blend of sweet, golden onions and creamy, melty brie, all nestled on flaky puff pastry.
Rich in good fats and a modest source of protein, they provide a satisfying, fiber-friendly snack.
Quick to assemble and bake, they make a perfect everyday appetizer, party treat, or easy weeknight indulgence.
Caramelized Onion Brie Tarts
Equipment
- 1 HexClad Hybrid Nonstick 2-Quart Saucepan with Tempered Glass Lid
- 1 MMmat Silicone Half Sheet Baking Mat (set of 2)
- 1 USA Pan Bakeware Half Sheet Pan (set of 2)
- 1 whisk
- 1 knife
Ingredients
- 3 sheets puff pastry thawed
- 2 yellow onions thinly sliced
- 2 tablespoons salted butter
- 1 ½ tablespoons balsamic vinegar
- ⅛ teaspoon sea salt
- ½ teaspoon brown sugar
- 1 egg
- 1 teaspoon water
- 8 ounces brie cheese wheel
Instructions
- Preheat Oven and Prepare Baking Surface: Preheat your oven to 400°F (200°C) to ensure the puff pastry bakes evenly and turns a golden-brown color. While the oven heats, line a half-sheet pan with parchment paper or a silicone baking mat. This will prevent sticking, make cleanup simple, and provide a stable surface for the pastries to puff evenly during baking.
- Caramelize Onions: Melt 2 tablespoons of salted butter in a medium saucepan over medium heat. Add the thinly sliced yellow onions and stir occasionally to ensure even cooking. Allow the onions to cook slowly for at least 20 minutes until they turn a rich golden-brown color and release a naturally sweet aroma. Patience during this step is crucial, as slow caramelization brings out the deepest, most flavorful sweetness.
- Add Flavor Enhancers: Once the onions are caramelized, stir in 1 ½ tablespoons of balsamic vinegar, ⅛ teaspoon of sea salt, and ½ teaspoon of brown sugar. Continue cooking for an additional 5 minutes, stirring frequently, until the mixture reaches a thick, jam-like consistency. Remove the pan from heat and allow the onion mixture to cool slightly before assembling the tarts.
- Prepare Puff Pastry Base: Take the 3 thawed sheets of puff pastry and place them on a clean work surface. Cut each sheet into squares roughly 3×3 inches. On each square, create an L-shaped cut along the bottom and right-hand side, and an upside-down L on the opposite corners. Fold each cut corner gently over to the opposite side, forming raised edges that will hold the brie and onions in place during baking, creating a small “boat” shape for the filling.
- Make Egg Wash: In a small bowl, whisk together 1 egg and 1 teaspoon of water until the mixture is smooth and frothy. This egg wash will give the pastry a beautiful golden-brown shine, enhancing both flavor and visual appeal. Brushing the edges ensures the tarts look polished and professional once baked.
- Assemble the Tarts: Place each puff pastry square on the prepared baking sheet. Brush the edges of each square with the egg wash to create a glossy finish. Slice the 8-ounce wheel of brie into small pieces or chunks and place one piece in the center of each pastry square. Spoon a generous amount of the caramelized onion mixture over the brie, filling the “boat” without overflowing excessively.
- Bake Until Golden: Transfer the baking sheet to the preheated oven and bake for approximately 20 minutes. Watch as the puff pastry rises and becomes golden-brown, while the brie melts and bubbles slightly. Remove the tarts when they are evenly browned and the filling is hot and creamy.
- Cool and Serve: Carefully remove the tarts from the oven and allow them to cool for a few minutes. Cooling slightly helps the cheese set a little, making the tarts easier to handle. Some brie may have leaked during baking, which is normal and adds a rustic charm. Serve warm as a satisfying appetizer, elegant party bite, or simple snack.
Notes
- Ensure puff pastry is fully thawed before cutting; this prevents cracking and makes folding easier.
- Slice onions thinly for even caramelization and the perfect jam-like texture.
- Stir onions gently but regularly during cooking to avoid burning and ensure uniform sweetness.
- Egg wash is optional but highly recommended for a shiny, golden finish.
- Brie may ooze during baking—this is normal and adds flavor, just place the tarts on a lined baking sheet to catch any overflow.
- Use a sharp knife for clean pastry cuts, and avoid pressing too hard when folding corners.
- Serve immediately for the best texture, though the tarts can be reheated gently.
Chef’s Secrets for Perfect Flavor
The key to achieving truly irresistible Caramelized Onion Brie Bites is patience and balance.
Slow-cook the onions over medium heat—rushing this step leads to uneven caramelization and a less sweet, less flavorful topping.
Choosing a creamy, high-quality brie enhances the richness without overpowering the onions.
When folding the pastry, gently press the corners to create a “boat” effect, ensuring the cheese and onions stay neatly inside while baking.
Finally, brushing the edges with egg wash guarantees a golden, glossy finish, elevating both appearance and flavor.
Serving Suggestions for Elegant Presentation
These tarts make a versatile appetizer suitable for both casual and formal gatherings.
Serve them warm, directly from the oven, on a wooden board or decorative platter.
Pair with fresh greens, figs, or lightly dressed arugula to balance the richness of the brie.
For a more indulgent spread, offer a side of tangy mustard, fig jam, or a drizzle of honey.
They also pair beautifully with sparkling wine, light white wine, or even a crisp cider for a complete, crowd-pleasing presentation.
Storage Tips to Maintain Freshness
Caramelized Onion Brie Bites are best enjoyed fresh from the oven but can be stored carefully for later.
Allow the tarts to cool completely before placing them in an airtight container.
Refrigerate for up to 3 days and reheat in a 350°F (175°C) oven for 5–8 minutes to restore flakiness.
Avoid microwaving, which can make the pastry soggy.
You can also freeze unbaked assembled tarts on a baking sheet, then transfer to a freezer-safe container for up to 2 months; bake directly from frozen, adding a few extra minutes to the cooking time.
Frequently Asked Questions
1. Can I make these tarts ahead of time?
Yes! You can assemble the tarts a few hours ahead and keep them covered in the refrigerator. Bake them just before serving to maintain the puff pastry’s crispiness and the brie’s creamy texture.
2. Can I use a different type of cheese?
While brie is ideal for its creamy, melty texture, you can substitute with camembert, mild goat cheese, or a soft Havarti. Hard cheeses are not recommended, as they won’t melt properly.
3. Can I use store-bought caramelized onions?
Yes, pre-cooked caramelized onions can save time. Just ensure they are drained of excess liquid to avoid soggy pastry and add a touch of balsamic vinegar for extra flavor.
4. How can I prevent the brie from leaking too much?
Trim the rind slightly if needed and place the cheese in the center of the folded “boat” pastry, leaving space around the edges. Using thicker slices helps the cheese hold its shape while melting.
5. Can I make these tarts gluten-free?
Absolutely. Use store-bought gluten-free puff pastry and follow the same instructions. Be aware that gluten-free pastry may bake slightly differently, so watch closely for browning and flakiness.
