Caramelized Onion and Gruyère Tart
A savory tart featuring sweet caramelized onions and nutty Gruyère cheese nestled in a flaky pastry crust. Ideal for brunches, appetizers, or light dinners.
- Author: Mariem
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Total Time: 45 minutes
- Yield: 6 slices 1x
- Category: Appetizer
- Method: Baked
- Cuisine: French
- Diet: Vegetarian
- 1 sheet puff pastry, thawed
- 2 tablespoons olive oil
- 2 large yellow onions, thinly sliced
- 1 teaspoon sugar
- 1/4 teaspoon salt
- 1/4 teaspoon black pepper
- 1 teaspoon fresh thyme leaves (optional)
- 1 cup grated Gruyère cheese
- 1 egg, beaten (for egg wash)
- Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
- Heat olive oil in a large skillet over medium heat. Add sliced onions, sugar, salt, and pepper. Cook, stirring often, for 25-30 minutes until onions are deeply golden and caramelized. Stir in thyme if using. Set aside to cool slightly.
- Roll out puff pastry on a lightly floured surface and place it on the prepared baking sheet. Score a 1-inch border around the edge with a sharp knife (do not cut all the way through).
- Spread the caramelized onions evenly within the border, then sprinkle Gruyère cheese on top.
- Brush the pastry edges with the beaten egg.
- Bake for 20-25 minutes, or until the pastry is puffed and golden brown.
- Let cool slightly before slicing and serving.
Notes
- Use a mandoline for evenly sliced onions to ensure uniform caramelization.
- Tart can be made ahead and reheated in a low oven before serving.
- Try adding a drizzle of balsamic glaze before serving for extra depth of flavor.
Nutrition
- Serving Size: 1 slice
- Calories: 290
- Sugar: 4g
- Sodium: 320mg
- Fat: 19g
- Saturated Fat: 10g
- Unsaturated Fat: 8g
- Trans Fat: 0g
- Carbohydrates: 22g
- Fiber: 1g
- Protein: 8g
- Cholesterol: 40mg
Keywords: caramelized onion tart, gruyère tart, savory pastry, French appetizer, vegetarian tart