Caramelized Onion and Gruyère Tart

• 1 sheet frozen puff pastry, thawed
• 2 tablespoons olive oil
• 2 large onions, thinly sliced
• 1 teaspoon sugar
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 1 cup shredded Gruyère cheese
• 2 large eggs
• 1/2 cup heavy cream
• 1 tablespoon fresh thyme leaves
• 1 egg beaten with 1 tablespoon water

Steps

1. 1 Preheat oven to 400°F. Line a baking sheet with parchment paper.
2. 2 Unfold puff pastry onto the prepared sheet and trim to desired tart shape.
3. 3 Heat olive oil in a large skillet over medium heat. Add onions, sugar, salt, and pepper. Cook until caramelized, about 20 minutes.
4. 4 Spread caramelized onions evenly over the puff pastry.
5. 5 Whisk together eggs, heavy cream, and thyme. Pour over onions.
6. 6 Sprinkle Gruyère cheese on top.
7. 7 Brush the edges of the pastry with beaten egg mixture.
8. 8 Bake for 25-30 minutes until pastry is golden and filling is set.
9. 9 Cool slightly before slicing and serving.

Equipment

• baking sheet
• parchment paper
• skillet
• mandoline (optional)
• whisk

Variations

• Add sautéed mushrooms or spinach for extra flavor and texture.

Substitutions

• Substitute Gruyère with Swiss cheese if needed.
• Use milk instead of heavy cream for a lighter version.

Pairings

• Mixed greens salad
• Roasted vegetables

Nutrition

Tips

• For best results, use a mandoline to slice onions uniformly.
• You can prepare the tart up to the baking stage and refrigerate for up to 2 hours before cooking.

Storage

Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat in a 350°F oven until warmed through.

Freezing: This tart freezes well for up to 1 month. Thaw overnight in the refrigerator and reheat in a 350°F oven.

Serving Suggestions

• Serve with a crisp green salad.
• Pair with a glass of Chardonnay for a delightful lunch or brunch.

FAQ