Viral Upside-Down Onion & Gruyere Pastry
Caramelized onions and gruyere baked under flaky puff pastry.
In a nutshell: This authentic french viral upside-down onion & gruyere pastry comes together in just 35 mins using simple whole ingredients. Perfect for home cooks seeking a dependable, restaurant-quality finish with minimal effort.
These viral upside-down tarts are gorgeous and incredibly easy. Slices of onion are caramelized directly on a baking sheet, topped with gruyere and puff pastry, then flipped over after baking.
Key Equipment
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Chef's Pro-Tips
- Keep the Pastry Cold: Work with well-chilled puff pastry straight from the fridge. Warm pastry won't separate into those distinct shattering layers in the oven.
- Flip While Hot: Turn each pastry over right out of the oven. Once the honey cools it acts like glue, and the onion topping will stick to the parchment instead of the pastry.
Ingredients
4
servings
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1 sheet puff pastry, thawed
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1 medium red onion, sliced into rings
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½ cup gruyere cheese, shredded
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2 tbsp honey
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1 tbsp olive oil
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1 large egg, beaten for egg wash
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Step-by-Step Instructions
Prep Pastry and Onions
Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper. Cut the puff pastry sheet into 4 equal rectangles.
Assemble Upside-Down
Drizzle 4 small circles of honey and olive oil onto the parchment. Place a thick slice of red onion ring on top of each circle. Sprinkle shredded Gruyere cheese over the onions.
Cover and Bake
Place a puff pastry rectangle over each cheese-and-onion pile, pressing the edges down with a fork to seal. Brush the pastry with egg wash and bake for 18-20 minutes until puffed and deep golden-brown. Flip carefully while warm.
Chef Clara's Kitchen Picks
Kitchen EssentialsAs an Amazon Associate I earn from qualifying purchases.
Nordic Ware Naturals Half Sheet, 2-Pack
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Non-stick paper for lining pans – easy release, easy cleanup.
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Silicone whisks safe for nonstick pans, in two sizes.
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Stainless racks that fit half sheets – for cooling bakes and crisping roasts.
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View on AmazonFrequently Asked Questions
The honey caramel is still fluid when warm, so the pastries release cleanly. Once it cools and sets, they stick to the parchment.
Yes. Any good melting cheese works. Gruyere is nutty and classic here, but fontina, comté, or sharp cheddar are great swaps.
The oven must be fully preheated to 400°F, and the pastry must stay cold until it goes in. Warm pastry melts instead of puffing into layers.
Absolutely. The upside-down technique works with tomato and mozzarella, apple and brie, or pear and blue cheese using the same method.
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