Go Back
french onion tart

french onion tart

This delightful French Onion Tart features a crispy pastry base filled with caramelized onions, creamy cheese, and aromatic herbs. It's perfect as an appetizer or a light main dish.
Print Recipe Pin Recipe
Prep Time 20 minutes
Cook Time 40 minutes
Total Time 1 hour
Course Appetizer
Cuisine French
Servings 4 People
Calories 300 kcal

Equipment

  • 1 tart pan (9-inch)
  • 1 frying pan
  • 1 mixing bowl
  • 1 rolling pin
  • 1 whisk
  • 1 oven

Ingredients
  

  • 1 sheet pre-made puff pastry Around 10 oz or 280 g.
  • 4 medium onions Approximately 2 lbs or 900 g, thinly sliced.
  • 2 tablespoons olive oil
  • 1 tablespoon butter
  • 1 teaspoon sugar
  • 1 teaspoon salt
  • 1 teaspoon black pepper
  • 1 teaspoon fresh thyme leaves Or ½ teaspoon dried thyme.
  • 1 cup Gruyère cheese, grated Approximately 100 g.
  • 2 large eggs
  • 1 cup heavy cream Approximately 240 ml.

Instructions
 

  • Preheat your oven to 375°F (190°C).
  • In a frying pan, heat the olive oil and butter over medium heat. Add the sliced onions and sugar. Cook, stirring occasionally, until the onions are caramelized and golden brown, about 20 minutes.
  • Season the onions with salt, pepper, and thyme, then set aside to cool slightly.
  • Roll out the puff pastry on a lightly floured surface to fit your tart pan. Place the pastry in the tart pan, trimming any excess.
  • In a mixing bowl, whisk together the eggs and heavy cream. Stir in the grated Gruyère cheese, and add the cooled onions.
  • Pour the onion and cheese mixture into the pastry shell, spreading it evenly.
  • Bake the tart in the preheated oven for 30-35 minutes, or until the pastry is golden brown and the filling is set.
  • Allow the tart to cool slightly before slicing. Serve warm or at room temperature.

Notes

You can add a splash of balsamic vinegar to the onions during cooking for an extra depth of flavor.
This tart can be made a day in advance and reheated.
Serve with a simple green salad for a complete meal.