Onion Tart with Caramelized Onions and Gruyère Recipe
A classic French-inspired Onion Tart featuring a buttery shortcrust pastry filled with sweet caramelized onions and a rich, creamy cheese custard. Perfect as a savory brunch dish, light lunch, or elegant appetizer, this tart combines the deep flavors of slowly sautéed onions with the creamy tang of cheese and eggs baked to golden perfection.
- Prep Time: 40 minutes
- Cook Time: 30 minutes
- Total Time: 1 hour 10 minutes
- Yield: 6 servings
- Category: Tart
- Method: Baking
- Cuisine: French
- Diet: Vegetarian
Ingredients
For the crust (shortcrust pastry):
- 200 g all-purpose flour
- 100 g cold unsalted butter, cut into cubes
- 1 egg
- A pinch of salt
- 1-2 tbsp cold water
For the filling:
- 3-4 large onions (about 500 g), thinly sliced
- 30 g unsalted butter
- 100 ml heavy cream (20-30% fat)
- 2 eggs
- 100 g hard cheese (such as Gruyère, Parmesan, or Cheddar), grated
- Salt and pepper to taste
- A pinch of nutmeg (optional)
Instructions
- Prepare the dough: In a large bowl, combine the flour, salt, and cold butter cubes. Use your fingers to rub the butter into the flour mixture until it resembles fine breadcrumbs. This will create the crumbly texture for the shortcrust pastry.
- Add egg and water: Incorporate the egg and add 1-2 tablespoons of cold water. Knead gently until the dough comes together smoothly, forming a cohesive ball. Be careful not to overwork the dough to keep it tender.
- Chill the dough: Wrap the dough ball tightly in cling film and refrigerate for 30 minutes. This resting helps relax the gluten and firms up the butter for easier rolling.
- Caramelize the onions: While the dough cools, melt the butter over medium heat in a large skillet. Add the thinly sliced onions and sauté gently for about 20 minutes, stirring frequently until they turn soft, translucent, and caramelized but not burnt. This slow cooking develops their natural sweetness.
- Mix the filling: In a separate bowl, whisk together the eggs and heavy cream until smooth. Stir in the grated cheese, salt, pepper, and optional nutmeg to create a flavorful custard base.
- Roll out the dough: On a lightly floured surface, roll out the chilled dough to fit a 23 cm tart pan. Gently press the dough into the pan, shaping the edges neatly. Prick the base several times with a fork to prevent bubbling during baking.
- Assemble the tart: Spread the caramelized onions evenly over the pastry base. Pour the creamy cheese and egg mixture on top of the onions, ensuring even coverage.
- Bake the tart: Place the tart in a preheated oven at 180°C (350°F) and bake for 25-30 minutes. Bake until the filling is golden, puffed, and set in the center.
- Cool and serve: Allow the tart to cool slightly to firm up for easier slicing. Serve warm or at room temperature as a delicious savory treat.
Notes
- For extra flavor, you can add fresh herbs like thyme or rosemary to the caramelized onions.
- If you prefer a crisper crust, blind bake the dough for 10 minutes before adding the filling.
- Use a tart pan with a removable bottom for easier slicing and serving.
- This tart is delicious served alongside a fresh green salad for a complete meal.
- Leftovers keep well refrigerated for 2-3 days and can be reheated gently in the oven.
