Viral Upside-Down Onion & Gruyere Pastry
Caramelized onions and gruyere baked under flaky puff pastry.
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
- Chef's Knife
- Cutting Board
- Measuring Cups & Spoons
- Baking Sheet
Chef's Pro-Tips
- Mise en Place: Measure and prep all ingredients before you turn on the stove. This recipe moves quickly, and having everything ready prevents burning.
- Fresh is Best: Whenever possible, use freshly squeezed lemon juice, whole garlic cloves, and fresh herbs instead of dried/jarred versions. The flavor difference is huge!
- Don't Crowd the Pan: Leave room between ingredients. If the pan is overloaded, the moisture will steam the food instead of browning it.
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
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.
Frequently Asked Questions
Allow the food to cool to room temperature, then transfer it to an airtight container. Store in the refrigerator for up to 3-4 days. Reheat gently on the stovetop or in the microwave.
We do not recommend freezing this dish, as dairy-based sauces and creamy textures tend to separate and curdle when thawed.
Use our interactive servings adjuster at the top of the ingredients list! Simply click the '+' or '-' buttons to automatically scale all ingredient quantities up or down to match your guest count.
Absolutely! For gluten-free modifications, swap standard grains or soy sauces with tamari or certified gluten-free options. For plant-based alternatives, choose coconut milk or vegetable broth in place of dairy and chicken products.