Upside Down Onion Tarts Recipe

Introduction

These Upside Down Onion Tarts combine the sweetness of caramelized onions with rich Swiss and Parmesan cheeses encased in flaky puff pastry. They’re elegant yet easy to make, perfect for a delicious appetizer or a light meal.

Ingredients

• 1 17 oz box puff pastry, thawed
• 4 tablespoons olive oil
• 2 tablespoons premade balsamic glaze
• 1-2 medium sweet onions, sliced into rounds
• 1 teaspoon garlic powder
• Salt and pepper to taste
• 12 slices Swiss cheese
• ¼ cup shredded Parmesan cheese
• 1 egg white

Instructions

1. Step 1: Preheat the oven to 400°F (200°C) and line two baking sheets with parchment paper.
2. Step 2: Cut the puff pastry into squares, about six squares per sheet, and set them aside.
3. Step 3: On each baking sheet, make six small pools of olive oil (twelve total) and drizzle balsamic glaze over each pool.
4. Step 4: Place an onion slice on top of each oil-and-glaze pool and sprinkle with garlic powder, salt, and pepper.
5. Step 5: Top each onion slice with a slice of Swiss cheese and a sprinkle of Parmesan cheese.
6. Step 6: Cover each with a pastry square, pressing the edges down to seal the tart.
7. Step 7: Brush the tops of the pastries with egg white to achieve a golden finish when baked.
8. Step 8: Bake for 12-15 minutes, or until the tarts are puffed and golden brown.
9. Step 9: Cool the tarts for 5 minutes, then carefully flip them upside down. Drizzle with extra balsamic glaze if desired before serving.

Tips & Variations

• Use sweet onions like Vidalia for the best balance of flavor and sweetness.
• Try adding fresh thyme or rosemary to the onions for an herby twist.
• Substitute provolone or gruyère cheese in place of Swiss for a different cheese flavor.
• For a crisper crust, chill the puff pastry before baking.

Storage

Store leftover tarts in an airtight container in the refrigerator for up to 3 days. Reheat in a 350°F (175°C) oven for 5-7 minutes to restore crispiness. They are best enjoyed fresh but still delicious warmed.

How to Serve

Serve this delicious recipe with your favorite sides.

FAQs

Can I make these tarts ahead of time?

Yes, you can assemble the tarts a few hours ahead and keep them refrigerated. Bake them just before serving for the best texture.

What can I use if I don’t have balsamic glaze?

If you don’t have balsamic glaze, reduce balsamic vinegar over low heat until it thickens or substitute with a drizzle of honey mixed with a splash of vinegar for sweetness and tang.

Upside Down Onion Tarts Recipe

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★★★★★

4.8 from 629 reviews

These Upside Down Onion Tarts feature sweet caramelized onions layered with Swiss and Parmesan cheese, all encased in golden, flaky puff pastry. Enhanced with a touch of balsamic glaze and garlic powder, these tarts are perfect as an elegant appetizer or savory snack. They bake to a crisp, golden finish and are served flipped upside down for a beautiful presentation.

• Author: Victoria
• Prep Time: 15 minutes
• Cook Time: 12-15 minutes
• Total Time: 30 minutes
• Yield: 12 tarts 1x
• Category: Appetizer
• Method: Baking
• Cuisine: American
• Diet: Vegetarian

Ingredients

Scale 1x2x3x

Puff Pastry and Bases

• 1 17 oz box puff pastry, thawed
• 4 tablespoons olive oil
• 2 tablespoons premade balsamic glaze, plus extra for drizzling

Onion Layer

• 1–2 medium sweet onions, sliced into rounds
• 1 teaspoon garlic powder
• Salt and pepper to taste

Cheese Layer

• 12 slices Swiss cheese
• ¼ cup shredded Parmesan cheese

Finishing

• 1 egg white, for brushing

Instructions

1. Preheat oven: Preheat your oven to 400°F (200°C). Line two baking sheets with parchment paper to prevent sticking and to ensure even baking.
2. Prepare pastry squares: Cut each puff pastry sheet into six equal squares, creating twelve squares total. Set these aside for assembling the tarts.
3. Create olive oil and balsamic bases: On each prepared baking sheet, spoon twelve small pools of olive oil (approximately twelve in total across both sheets). Drizzle a small amount of balsamic glaze over each olive oil pool to add sweetness and depth.
4. Layer onions and season: Place one sweet onion round on top of each olive oil and balsamic pool. Evenly sprinkle garlic powder, salt, and pepper over the onions for enhanced flavor.
5. Add cheese layers: Place one slice of Swiss cheese on top of each onion round, then sprinkle each with a bit of shredded Parmesan cheese to add richness and a savory touch.
6. Seal with puff pastry: Carefully place a puff pastry square over each cheese-topped onion stack. Press down firmly around the edges to seal the tarts and prevent filling from leaking out during baking.
7. Brush with egg white: Lightly brush the surface of each pastry with egg white. This will help the tarts achieve a beautiful golden brown and glossy finish once baked.
8. Bake the tarts: Bake the prepared baking sheets in the oven for 12-15 minutes, or until the puff pastry is fully puffed and turns a deep golden brown color.
9. Cool and flip: Remove the tarts from the oven and allow them to cool for about 5 minutes. Carefully flip each tart upside down to reveal the caramelized onion and cheese topping.
10. Optional glazing: For an extra burst of flavor and attractive presentation, drizzle additional balsamic glaze over the tops of the flipped tarts before serving.

Notes

• You can add fresh herbs like thyme or rosemary to the onion layer for an aromatic twist.
• Ensure the puff pastry is properly thawed before cutting to avoid cracking or tearing.
• Use a sharp knife or pizza cutter for clean pastry squares.
• Serve these tarts warm for the best texture and flavor.
• Leftover tarts can be stored in an airtight container in the refrigerator for up to 3 days and reheated in an oven or air fryer to maintain crispness.

Keywords: upside down onion tarts, puff pastry tarts, savory tarts, Swiss cheese tarts, easy appetizer recipes, balsamic glaze tarts, onion cheese pastry