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Caramelized Onion & Gruyère Tart

Caramelized Onion & Gruyère Tart

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Prep Time 20 minutes
Cook Time 45 minutes
Total Time 1 hour 5 minutes
Servings: 6
Course: Appetizer, Brunch, Dinner
Cuisine: French
Calories: 320
Ingredients Method Notes

Ingredients
  

  • 1 sheet puff pastry thawed
  • 3 large yellow onions thinly sliced
  • 1 ½ cups shredded Gruyère cheese
  • 2 tbsp olive oil
  • 1 tbsp butter
  • 1 tsp fresh thyme or ½ tsp dried
  • Salt & black pepper
  • 1 egg for egg wash
  • Optional: 2–3 tbsp white wine or balsamic vinegar

Method
 

  1. Preheat oven to 400°F.
  2. Lay puff pastry on a parchment-lined baking sheet and score a 1-inch border.
  3. Caramelize onions in butter + olive oil for 35–45 minutes until deep golden. Add salt and optional wine or balsamic.
  4. Spread onions onto pastry inside the border. Add ½ the cheese, thyme, then remaining cheese.
  5. Brush edges with egg wash.
  6. Bake 22–28 minutes, until golden and puffed.
  7. Cool 5 minutes, slice, serve warm.

Notes

  • Don’t rush the onions. True caramelization takes time.
  • Use freshly shredded Gruyère for best melt.
  • Let pastry thaw fully before unfolding.
  • Bake on parchment to prevent sticking.