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Caramelized Onion and Gruyère Tart

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A savory tart featuring sweet caramelized onions and nutty Gruyère cheese nestled in a flaky pastry crust. Ideal for brunches, appetizers, or light dinners.

Ingredients

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  • 1 sheet puff pastry, thawed
  • 2 tablespoons olive oil
  • 2 large yellow onions, thinly sliced
  • 1 teaspoon sugar
  • 1/4 teaspoon salt
  • 1/4 teaspoon black pepper
  • 1 teaspoon fresh thyme leaves (optional)
  • 1 cup grated Gruyère cheese
  • 1 egg, beaten (for egg wash)

Instructions

  1. Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
  2. Heat olive oil in a large skillet over medium heat. Add sliced onions, sugar, salt, and pepper. Cook, stirring often, for 25-30 minutes until onions are deeply golden and caramelized. Stir in thyme if using. Set aside to cool slightly.
  3. Roll out puff pastry on a lightly floured surface and place it on the prepared baking sheet. Score a 1-inch border around the edge with a sharp knife (do not cut all the way through).
  4. Spread the caramelized onions evenly within the border, then sprinkle Gruyère cheese on top.
  5. Brush the pastry edges with the beaten egg.
  6. Bake for 20-25 minutes, or until the pastry is puffed and golden brown.
  7. Let cool slightly before slicing and serving.

Notes

  • Use a mandoline for evenly sliced onions to ensure uniform caramelization.
  • Tart can be made ahead and reheated in a low oven before serving.
  • Try adding a drizzle of balsamic glaze before serving for extra depth of flavor.

Nutrition

Find it online: https://tastyera.com/caramelized-onion-and-gruyere-tart/