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Upside-Down Caramelized Onion Tarts

These elegant tarts feature crispy puff pastry topped with sweet, caramelized onions, perfect for impressing guests at any occasion.
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Prep Time 15 minutes
Cook Time 40 minutes
Total Time 55 minutes
Servings: 6 servings
Course: Appetizer, Snack
Cuisine: French
Calories: 250
Ingredients Method Notes

Ingredients
  

For the Tarts
  • 1 lb Puff Pastry Thawed if frozen
  • 2 tbsp Butter Melted
  • 1 tbsp Olive Oil For cooking onions
  • 3 large Yellow Onions Thinly sliced
  • 1 tbsp Balsamic Vinegar Adds flavor to onions
  • 1 tsp Honey or Brown Sugar To enhance sweetness of onions
  • 1 tbsp Fresh Thyme Or to taste

Method
 

Preparation
  1. Preheat the oven to 400°F (200°C). Cut the puff pastry into rounds or squares slightly larger than the portions you’re making. Keep the pastry refrigerated while preparing the onions.
  2. Melt 2 tablespoons of butter with 1 tablespoon of olive oil in a large oven-safe skillet over medium-low heat. Add the sliced onions along with a pinch of salt and thyme leaves. Cook for about 20–25 minutes, stirring occasionally until the onions are very soft and golden.
  3. Add balsamic vinegar and honey or brown sugar, and cook for another 2–3 minutes until glossy with very little liquid left in the pan.
Assembly
  1. Arrange the caramelized onions in the skillet or in individual oven-safe tart dishes. Lay the puff pastry over the onions, tucking the edges down.
  2. Prick the pastry with a fork and brush lightly with beaten egg.
Baking
  1. Bake for 20–25 minutes or until the pastry is golden brown. Let cool for 5 minutes, then flip onto plates to serve.

Notes

Serve warm as an appetizer or light meal. Pairs well with a fresh salad or white wine. Can add cheese like goat cheese or Gruyère for extra flavor. Leftovers can be stored in an airtight container for up to 3 days.