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ELEGANT BITES
Caramelized Onion and Gruyère Puff Pastry Tarts
★★★★★
5.0 (230)|(2 Reviews)Flaky all-butter puff pastry topped with jammy balsamic caramelized onions, melted Swiss Gruyère, and fresh fragrant thyme.
L
By Lou Perseghin (Test Kitchen Specialist)•Published July 11, 2026
⏱ 50 mins
Simply Recipes / Lou Perseghin🔥 210 kcal
WHY MAKE THIS
- Looks and tastes like it came from a Parisian patisserie.
- Onions can be caramelized up to 3 days in advance.
- Flaky, golden-brown crust with irresistible savory cheese edges.
ELEGANT BITES
Caramelized Onion and Gruyère Puff Pastry Tarts
French bakery elegance made accessible at home. Sweet, slow-cooked onions combined with nutty Gruyère cheese over shattered layers of crisp golden puff pastry.
Prep Time15 mins
Cook Time35 mins
Total Time50 mins
Servings8 servings
Scale Recipe:
📱Keep Screen Awake While Cooking
Ingredients
- 1 sheet frozen puff pastry (all-butter preferred), thawed
- 2 large yellow onions, thinly sliced
- 2 tbsp unsalted butter
- 1 tbsp extra virgin olive oil
- 1 tbsp balsamic vinegar
- 1 tsp fresh thyme leaves (plus extra for garnish)
- 1 1/2 cups shredded Gruyère cheese
- 1 large egg beaten with 1 tbsp water (egg wash)
- 1/2 tsp kosher salt & 1/4 tsp black pepper
Directions
1
Caramelize the onions
Melt butter and olive oil in a skillet over medium-low heat. Add onions and cook slowly for 20–25 minutes until deeply caramelized and golden brown. Stir in balsamic vinegar, thyme, salt, and pepper. Let cool.
2
Prep pastry
Preheat oven to 400°F (200°C). Unroll puff pastry onto a parchment-lined baking sheet. Score a 1/2-inch border around the edge with a knife and prick the center with a fork.
3
Assemble toppings
Scatter 1 cup of Gruyère within the border, top with caramelized onions, and finish with remaining cheese. Brush edges with egg wash.
4
Bake until golden
Bake for 18–20 minutes until pastry is puffed and golden brown. Cut into squares and serve warm.
💡 CHEF'S PRO TIPS
- Keep the puff pastry cold right until baking so the butter layers expand into maximum flaky puffiness.
- Gruyère can be substituted with sharp Swiss cheese or white cheddar.
Nutrition Facts
Per ServingCalories210 kcal
Protein7g
Carbs17g
Total Fat13g
Sodium: 220mg
Fiber: 1g
Sugar: 2g
Community Reviews & Ratings
2 cooks have shared their thoughts on this recipe
S
Sarah M.★★★★★
This has completely replaced my normal avocado toast! The beans blend so well you cannot even tell, and I stay full until lunchtime!
D
David K.★★★★★
Great trick for adding protein without cooking eggs on busy mornings. Added a pinch of red pepper flakes and lemon zest—delicious.
