Caramelized Onion Tart with Gruyere
Sweet caramelized onions and gruyere cheese on flaky puff pastry. All the flavors of French onion soup in an easy appetizer! Make it as one large tart or individual bites.
Servings: 6
Ingredients
- 1 sheet puff pastry Trader Joe's puff pastry works great here
- 2 large onions (yellow or sweet) thinly sliced
- 1 tablespoon olive oil
- 1 tablespoon butter
- 4 sprigs fresh thym
- ¼ teaspoon salt
- ½ cup gruyere cheese grated
Instructions
Onion Filling
- Remove puff pastry from freezer and let thaw in the refrigerator overnight, or on the counter for 1 to 2 hours. Keep refrigerated until ready to use.
- Heat a heavy bottom pan over medium heat. Add oil, then butter, and let it melt.
- Add onions and stir until coated and softened, about 5 minutes. Sprinkle salt and add thyme.
- Cook onions over low to medium heat for about 30-45 minutes, stirring occasionally. Add more butter or oil if needed thruughout.
- Once the onions are soft, fragrant, and deep golden brown, remove from heat and cool completely.
Assemble the Tart
- Preheat oven to 400℉
- Roll out puff pastry on a parchment lined baking sheet.
- Use a fork to gently poke holes throughout the puff pastry.
- Spread cooled caramelized onions evenly over pastry, leaving a 1-inch border around edges.
- Sprinkle grated Gruyere cheese evenly over the onions. Fold the edges inward over the filling to create a border crust.
- Bake on the middle rack for 10-12 minutes, or until golden brown.
- Once cooled, slice into squares or triangles and serve.
Notes
- Keep puff pastry cold until ready to use
- Don't rush the caramelization process , patience is key!
- Onion filling can be made a day ahead and stored in the fridge.