Flamiche aux Poireaux — Picardy Leek Tart

Ingredients

• For the tart shell
• 1 × 26 cm pâte brisée (or puff pastry), enough to line a 26 cm tart ring
• as needed dried baking beans, for blind-baking
• For the leeks
• 800 g leeks, white and pale green parts only, sliced into 5 mm rounds
• 50 g unsalted butter
• 1 pinch fine salt
• 1 pinch ground white pepper
• 1 pinch freshly grated nutmeg
• For the custard
• 2 whole eggs
• 2 egg yolks
• 250 ml double cream

Method

1. 1
   Melt the butter in a wide, heavy pan over medium-low heat. Add the sliced leeks and cook, stirring regularly, for 20–25 minutes. The leeks must collapse to roughly half their raw volume and become completely soft and sweet. They must not colour at any point — the moment the pan shows any browning, reduce the heat immediately. Season with salt, white pepper, and nutmeg. Remove from heat and allow to cool slightly.
2. 2
   Line a 26 cm tart ring with the pâte brisée. Blind-bake at 180 °C with baking beans for 15 minutes, then remove the beans and bake a further 5 minutes. The shell is ready when it is pale gold and the base feels dry to the touch.
3. 3
   Whisk the 2 whole eggs and 2 yolks together with the 250 ml of double cream. Season with salt and white pepper.
4. 4
   Spread the cooled leeks evenly across the blind-baked shell. Pour the custard over them; it should fill the shell to just below the rim.
5. 5
   Bake at 170 °C for 30–35 minutes. The tart is done when the surface is golden and the centre retains a gentle, trembling wobble when the tin is moved. A custard that has set rigid has been taken too far.
6. 6
   Rest the tart on a rack for 10–15 minutes before cutting. Serve warm, never hot. The filling should be silky and barely set, the leeks sweet and yielding throughout, the pastry crisp and shattering.