Upside Down Onion Tarts
Delightfully savory and sweet, these upside down onion tarts boast caramelized onions and Gruyere cheese nestled beneath crisp, golden puff pastry—ideal for a refined appetizer or a satisfying snack.
Ingredients
- 1 tablespoon balsamic vinegar
- 3 tablespoons honey
- 1 sheet puff pastry thawed
- Fresh thyme leaves salt, and black pepper, to taste
- 1 teaspoon chili flakes
- 3 sweet onions thinly sliced
- 1 egg beaten
- 18 slices Gruyere cheese thinly sliced (or as needed)
Instructions
- Begin by preheating the oven to 400°F. Prepare the puff pastry by slicing it into rectangular portions while simultaneously organizing the onions and cheese.
- Line a baking tray with parchment paper, and in separate sections of the tray, add a drizzle of honey, a dash of balsamic vinegar, a sprinkle of chili flakes, and a few thyme leaves.
- Carefully place a slice of onion atop each mixture, followed by layering with slices of Gruyere cheese.
- Cover each assembly with a rectangle of puff pastry and brush the tops with the beaten egg.
- Transfer the tray to the oven and bake for 20 to 25 minutes, or until the pastry is golden and the onions are thoroughly caramelized.
Notes
Ensure the puff pastry is completely thawed before use to achieve optimal flakiness and ease of handling. For enhanced depth of flavor, consider dusting the onion slices with a pinch of beef or mushroom bouillon powder prior to topping with pastry. Once baked, allow the tarts to rest briefly and gently run a knife underneath to loosen before serving.