Tarte aux oignons – caramelised onion and cheese tart Recipe
A savoury French tart with plenty of slowly sautéed onions and cheese is a great dish for dinner or a get-together with friends. The onions turn sweet and soft, and the whole thing is reminiscent of a cross between pizza and an onion flatbread, but on a crisp, buttery shortcrust base. Tarts like this often appear in small bistros in northern France as a warm starter.
This tart showcases how simple ingredients like onions and cheese can turn into an elegant, bistro-style dish thanks to slow caramelisation and a buttery shortcrust base. It’s impressive enough for guests, yet easy to prepare ahead of time.
Chef's tips
Take your time with the onions – don’t rush this step, as their sweetness and depth of flavour are key to the whole tart. If your kitchen is warm, chill the rolled-out dough in the tin for 10–15 minutes before blind-baking to keep the crust extra crisp and prevent shrinking.
How to serve
Serve the tart slightly warm with a green salad dressed with mustard vinaigrette and a glass of dry white wine or light cider. Cut into small squares for a finger-food style appetiser, or into larger wedges as a main course with salad and perhaps a light soup to start.
Ingredients
- wheat flour type 450–550 - 220 g
- butter cold, cut into cubes - 120 g
- egg for the dough - 1 piece
- water very cold - 2 tablespoon
- salt for the dough - 0.5 teaspoon
- onion regular yellow, peeled - 700 g
- oil for frying - 1 tablespoon
- butter for frying the onions - 1 tablespoon
- sugar for lightly caramelising the onions - 1 teaspoon
- thyme dried leaves or a few sprigs of fresh - 1 teaspoon
- cream 30% or 18% for sauces - 150 ml
- egg for the onion mixture - 2 piece
- yellow cheese hard, good melting, grated (e.g. Gruyère, Emmental) - 120 g
- salt to taste for the filling
- pepper freshly ground, to taste
Preparation
- Start with the dough: put the flour and salt into a bowl, add the cold butter. Rub with your fingers or cut with a knife until you get fine crumbs resembling wet sand.
- Add the egg and 1–2 tablespoons of very cold water. Quickly bring the dough together just until combined. Shape into a flattened disc, wrap in cling film and chill in the fridge for at least 30 minutes.
- Slice the onions into thin half-moons.
- Heat the oil with the butter in a large frying pan over medium heat. Add the onions, a pinch of salt and fry for 10 minutes, stirring often, until softened.
- Add the sugar and thyme, reduce the heat to low and cook for another 15–20 minutes, stirring every few minutes, until the onions are very soft, golden and slightly sweet. If they start to catch, lower the heat and add 1–2 tablespoons of water.
- Preheat the oven to 190°C (top and bottom heat). Lightly grease a tart tin about 26 cm in diameter or line it with baking paper.
- Roll out the chilled dough on a floured surface into a round slightly larger than the tin. Transfer to the tin, press into the base and sides, trim the excess. Prick the base with a fork.
- Cover the dough with baking paper, pour dry beans or rice on top as weights and blind-bake for 12 minutes. Remove the paper with the weights and bake for another 5 minutes, until the base is lightly golden.
- In a bowl, mix the cream with 2 eggs, add the grated cheese and season with salt and pepper. Add the cooled onions and mix thoroughly.
- Pour the onion mixture onto the pre-baked crust and smooth the top with a spoon.
- Bake the tart for 20–25 minutes at 190°C, until the filling is set and the top is golden. After removing from the oven, leave to stand for 10 minutes to firm up slightly before cutting into slices.
Storage
No storage information available for this dish.
This tart is inspired by simple French bistro cooking: a short list of ingredients, but plenty of flavour thanks to patience and good technique. It’s one of those recipes that quickly becomes a house favourite and works just as well for a weekday dinner as for a relaxed evening with friends.
