Can I make these tarts larger for a main dish?

Absolutely! Instead of cutting individual circles, you could make one large tart or several medium ones. Adjust baking time accordingly – larger tarts may need an extra 5-10 minutes in the oven.

My puff pastry isn't rising well around the edges. What went wrong?

The most common issues are overworking the dough, not having a clean cut around the edges, or having your oven temperature too low. Make sure your pastry is cold when it goes into a fully preheated oven, and that your knife or cutter makes clean, straight-down cuts without dragging through the dough.

Can I use yellow onions instead of the large onions called for?

Yes! Any onion variety works beautifully in this recipe. Sweet onions like Vidalia will give you a milder, sweeter result, while red onions add a slightly more robust flavor with beautiful color.

How do I know when my onions are properly caramelized?

Properly caramelized onions will be significantly reduced in volume (about 1/4 of their original size), uniformly golden to medium brown, and have a jam-like consistency. They should taste sweet with complex flavor, not burnt or bitter.

Caramelized Onion Tarts Recipe

Name: Caramelized Onion Tarts Recipe
Prep time: 20 min
Cook time: 1 h
Total time: 1 h 20 min
Cuisine: European
Ingredients: ½ batch rough puff pastry or classic puff pastry (or store-bought); 3 large onions, sliced thin; 2 tablespoons olive oil; ¼ teaspoon salt; 1 tablespoon balsamic vinegar; 3 ounces crumbled feta (about ¾ cup); Egg wash (1 egg whisked with a teaspoon of water); 1 small bunch of chives, sliced fine

Description

These Caramelized Onion Tarts are a perfect blend of flakey pastry, sweet caramelized onions, and tangy feta cheese. They’re elegant yet incredibly simple to prepare, making them perfect as an appetizer or a snack for any occasion. The crisp puff pastry and rich onion filling create a delightful bite-sized treat that is sure to be a crowd-pleaser.

Ingredients

Units Scale

For the Tart Base

1/2 batch rough puff pastry or classic puff pastry (or store-bought)

For the Caramelized Onions

3 large onions, sliced thin
2 tablespoons olive oil
1/4 teaspoon salt
1 tablespoon balsamic vinegar

Toppings

3 ounces crumbled feta (about 3/4 cup)
Egg wash (1 egg whisked with a teaspoon of water)
1 small bunch of chives, sliced fine

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Instructions

Prepare Puff Pastry:
If using homemade rough puff pastry, prepare and refrigerate ahead of time to allow it to rest. Use only half of the batch for this recipe; the remaining half can be frozen. Alternatively, if using store-bought puff pastry, defrost it according to package instructions.
Caramelize the Onions:
In a wide, heavy-bottomed pan, heat olive oil over medium heat. Add the sliced onions and cook for about 10 minutes, stirring occasionally so they soften evenly. Add a pinch of salt, stir, and reduce the heat to medium-low. Let the onions cook undisturbed for 20 minutes to develop their sweetness. Stir and continue cooking for another 15 minutes, stirring every 5 minutes to avoid sticking. Once they have achieved a golden-brown color, stir in the balsamic vinegar and cook for 5 more minutes. For deeply jammy onions, cook an extra 10 minutes (optional). Let the onions cool to room temperature.
Prepare the Filling:
Combine the cooled caramelized onions with the crumbled feta in a small bowl. This creates the signature tart filling.
Preheat the Oven:
Preheat your oven to 400ºF (200ºC) and line a 13×18” baking sheet with parchment paper.
Roll Out the Pastry:
On a lightly floured surface, roll out the puff pastry to about ⅛” thickness, forming a 10” x 14” rectangle. If using store-bought pastry, simply lay it out and dust lightly with flour to prevent sticking.
Cut the Dough:
Use a 3-inch circular cutter to stamp out 12 pastry rounds. Avoid re-rolling the scraps, though they can be used for other purposes.
Dock the Pastry:
With a 2-inch cutter, gently press into the center of each circle without cutting through. Dock the inner circle with a fork to prevent excessive puffing during baking.
Assemble the Tarts:
Place the pastry rounds evenly spaced on the baking sheet. Brush the edges with egg wash. Add a heaping tablespoon of the onion and feta mixture to the center of each tart.
Bake:
Bake the tarts on the middle oven rack for 15-18 minutes, or until the pastry is puffed and golden brown.
Garnish and Serve:
Allow the tarts to cool slightly, transfer them to a cooling rack, and sprinkle with fresh chopped chives. Serve warm or at room temperature.

Notes

Homemade puff pastry yields the best results, but store-bought works well for convenience. Be mindful of varying brand sizes, which may affect the final number of tarts.
Leftover caramelized onions can be refrigerated for up to 3 days or frozen for up to several months.
These tarts are best eaten fresh but can be stored in an airtight container in the refrigerator for up to 2 days. Reheat for a few minutes before serving. They can also be frozen but may lose a bit of crispness upon reheating.
Use smaller cutters for more tarts; adjust baking time accordingly.

Nutrition

Serving Size: 1 tart
Calories: 175kcal
Sugar: 3g
Sodium: 210mg
Fat: 12g
Saturated Fat: 6g
Unsaturated Fat: 6g
Trans Fat: 0g
Carbohydrates: 15g
Fiber: 1g
Protein: 4g
Cholesterol: 30mg