Onion Tart

Name: Onion Tart
Total time: 3 h 30 min
Yield: 8 servings
Ingredients: 350 g plain flour; 180 g cold unsalted butter; 2 tablespoons cold water; 1 kg brown onions; 60 ml olive oil; 4 pieces egg yolks; 250 ml pure cream; 1 pinch freshly grated nutmeg; 1 to taste sea salt and black pepper; 1 piece tart tin

A rich and savory French-style tart featuring caramelized brown onions in a creamy custard base, all nestled in a buttery homemade pastry shell. Perfect as a main dish or elegant appetizer.

8 servings

3 hr 30 min

Published October 4, 2025

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Ingredients

•350 g plain flour
•180 g cold unsalted butter
•2 tablespoons cold water
•1 kg brown onions
•60 ml olive oil
•4 pieces egg yolks
•250 ml pure cream
•1 pinch freshly grated nutmeg
•1 to taste sea salt and black pepper
•1 piece tart tin

Cooking Instructions

1.
To make the pastry, process the flour, butter and water together in a food processor for a few minutes until a rough dough forms. Remove, wrap in plastic wrap and refrigerate for 30 minutes.
35 min
2.
Preheat the oven to 180°C (350°F/Gas 4).
5 min
3.
Roll the dough out on a floured bench and gently press into the tin. Trim the pastry to fit and reserve the left-over pastry to patch any cracks.
10 min
4.
To blind-bake the tart, line the pastry shell with foil and fill with baking weights or uncooked rice or beans. Bake until cooked, about 20 minutes. Remove the foil and weights and bake for an additional 15-20 minutes until lightly golden. If there are any cracks, patch with the left- over pastry.
40 min
5.
While the tart shell is baking, prepare the filling.
5 min
6.
In a large frying pan over low to medium heat, sauté the onion in the oil until very soft and light brown. This may take up to an hour. Set aside to cool slightly. Beat the egg yolks with the cream. Add the nutmeg and season well with salt and pepper. Stir the onion through the cream mixture.
70 min
7.
Carefully fill the pastry shell with the filling, place in the oven and bake for 40-45 minutes, or until the filling is set. Serve warm or at room temperature.
45 min

Cooking Instructions

To make the pastry, process the flour, butter and water together in a food processor for a few minutes until a rough dough forms. Remove, wrap in plastic wrap and refrigerate for 30 minutes.

35 min

Preheat the oven to 180°C (350°F/Gas 4).

5 min

Roll the dough out on a floured bench and gently press into the tin. Trim the pastry to fit and reserve the left-over pastry to patch any cracks.

10 min

To blind-bake the tart, line the pastry shell with foil and fill with baking weights or uncooked rice or beans. Bake until cooked, about 20 minutes. Remove the foil and weights and bake for an additional 15-20 minutes until lightly golden. If there are any cracks, patch with the left- over pastry.

40 min

While the tart shell is baking, prepare the filling.

5 min

In a large frying pan over low to medium heat, sauté the onion in the oil until very soft and light brown. This may take up to an hour. Set aside to cool slightly. Beat the egg yolks with the cream. Add the nutmeg and season well with salt and pepper. Stir the onion through the cream mixture.

70 min

Carefully fill the pastry shell with the filling, place in the oven and bake for 40-45 minutes, or until the filling is set. Serve warm or at room temperature.

45 min