Ingredients Print

Check off ingredients as you go

Makes 1 tart, 26 cm (10 inches) in diameter (serves 4-6)

For the homemade pie dough

• 250 g (2 cups) all-purpose flour (plain flour), sifted
• 52 g (¼ cup) oil (olive or sunflower)
• 100 ml (⅓ cup + 1 Tbsp) lukewarm water
• 1 level tsp fine salt
• 1 tsp chopped herbs or seeds of your choice (oregano, herbes de Provence, poppy seeds)
• 1 Tbsp cornstarch or potato starch (optional, for extra crispness)

For the filling

• 600 g (1.3 lb) onions, thinly sliced (3 large onions)
• 150 g (⅔ cup) heavy cream
• 50 g (1.75 oz) sandwich bread or stale bread (2 slices sandwich bread)
• 80 g (⅓ cup) dry white wine (3/4 of a glass)
• 50 g (¼ cup) olive oil
• 1/2 tsp fine salt (3 g)
• 1 Tbsp all-purpose flour (10 g)
• 1 large egg (60 g)
• Pepper
• a few sprigs fresh thyme
• 1 Tbsp whole grain mustard (optional)
• a pinch of nutmeg or sugar (to mellow the onions)

If you change the number of serving, consider adjusting cooking times!

Making the onion tart

For the pie dough

1. In a large bowl or the bowl of a stand mixer fitted with the paddle, add the flour, starch, salt and herbs. Add the oil and mix with your fingertips until the texture is sandy. Pour in the water gradually and mix just enough to form a smooth ball. Let rest for 1 hour.

2. Roll out the dough on a lightly floured surface or between two sheets of parchment paper, then line the 26 cm (10-inch) pan.

3. Chill while you prepare the filling.

Tip for a crisp tart base: blind bake for 10 minutes at 180°C (350°F).

For the onion filling

1. Thinly slice the onions.

2. In a large skillet, heat the olive oil over low heat. Add the onions, a pinch of salt and a little sugar if you like, then let them cook down for 25 to 30 minutes, stirring regularly, until lightly golden.

3. Meanwhile, pour the white wine over the stale bread and mash it into a wet paste.

Assembling the onion tart

1. In a large bowl, beat the egg with the salt and pepper.
2. Add the flour, then the cream and finally the wine-soaked bread.
3. Fold in the warm onions and the chopped thyme. Mix gently.
4. Pour the filling over the dough.

4. Baking the onion tart

1. Preheat the oven to 190°C (375°F) fan/convection.
2. Bake in the middle of the oven for 35-40 minutes, until the tart is golden and the crust is fully cooked. Let cool for a few minutes before unmolding, and serve warm with a salad of lamb’s lettuce (mâche) or baby greens.

Variations: swap in ⅓ shallots for extra sweetness, or add a little whole grain mustard for a bolder flavor.