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Golden Caramelized Onion & Gruyère Puff Pastry Tart Recipe

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★★★★★

4.4 from 105 reviews

This Golden Caramelized Onion & Gruyère Puff Pastry Tart is a deliciously savory treat perfect for brunch, appetizers, or a light meal. Featuring sweet, slow-cooked onions paired with nutty Gruyère cheese atop a crisp, buttery puff pastry, this tart balances rich flavors and flaky textures beautifully. A hint of thyme and optional Dijon mustard add depth, making it an elegant yet easy-to-make dish.

Ingredients

Scale

Pastry Base

  • 1 sheet puff pastry, thawed (about 10×10 inches)
  • 1 egg, beaten (for brushing)
  • 1 tbsp Dijon mustard (optional, for flavor depth)

Caramelized Onions

  • 3 large yellow onions, thinly sliced
  • 2 tbsp butter
  • 1 tbsp olive oil
  • 1 tsp sugar
  • Salt, to taste
  • 1 tsp fresh thyme leaves (plus more for garnish)

Cheese Mixture

  • 1 cup (100 g) shredded Gruyère cheese
  • ¼ cup (60 ml) heavy cream
  • 1 egg
  • ½ tsp black pepper

Instructions

  1. Caramelize Onions: In a large skillet, melt butter with olive oil over medium heat. Add the thinly sliced onions, sugar, and a pinch of salt. Cook slowly, stirring frequently, for 25–30 minutes until the onions become golden brown and jammy. Stir in fresh thyme leaves and set the mixture aside to cool slightly.
  2. Preheat Oven and Prepare Pastry: Preheat your oven to 400°F (200°C). Place the thawed puff pastry sheet on a parchment-lined baking sheet. Using a knife, score a 1-inch border around the edges without cutting through. Lightly prick the inner area with a fork to prevent excessive puffing during baking.
  3. Blind Bake Pastry Base: Brush the edges of the puff pastry with beaten egg. Bake the pastry for 10 minutes until it turns lightly golden.
  4. Prepare Cheese Mixture: In a bowl, whisk together the heavy cream, egg, black pepper, and shredded Gruyère cheese until well combined.
  5. Assemble Tart: If using, spread Dijon mustard evenly over the pre-baked pastry base within the scored border. Pour the cheese mixture over the mustard layer evenly. Top generously with the caramelized onions on the cheese mixture.
  6. Bake Tart: Return the tart to the oven and bake for 15–18 minutes until the pastry is puffed and golden brown and the cheese filling is set.
  7. Garnish and Serve: Once baked, sprinkle fresh thyme leaves and a pinch of sea salt over the tart. Slice into squares and serve warm or at room temperature for best flavor.

Notes

  • Caramelizing onions requires patience; cook them slowly to develop deep, rich flavor.
  • The Dijon mustard is optional but adds a nice tangy depth to the tart.
  • Ensure the puff pastry is fully thawed before scoring and baking to avoid cracking.
  • Let the tart cool slightly before slicing to keep the cheese filling intact.
  • This tart can be served warm or at room temperature, making it great for entertaining.

Keywords: caramelized onion tart, Gruyère puff pastry tart, savory tart, French tart, caramelized onions, puff pastry recipe, appetizer recipes, easy baked tart

Find it online: https://nayabaker.com/golden-caramelized-onion-and-gruyere-puff-pastry-tart-recipe/