Lemon Tart

Name: Lemon Tart
Prep time: 45 min
Cook time: 5 h 35 min
Total time: 6 h 20 min
Cuisine: France
Ingredients: 1 batch sweet shortcrust, Shortcrust and Flaky Pastry, or 320 g store-bought sweet shortcrust; 1 egg white (about 30 g), lightly beaten, for sealing; 4 unwaxed lemons, zest of 2, juice of all 4 (you need 150 ml); 5 large eggs (about 250 g without shells); 175 g (¾ cup + 2 tbsp) superfine (caster) sugar; 150 ml (⅔ cup) heavy (double) cream; powdered (icing) sugar, for dusting, optional

Sharp, smooth lemon custard in a crisp, sweet pastry case

Makes: 1 tart (23 cm / 9 in, 3 cm deep)
Hands-on: 45 min
Total: 6 h 20 min
Level: Some skill

A crisp sweet-pastry shell filled with a smooth, intensely lemony baked custard that sets just enough to slice. It is sharp, clean-tasting and elegant, and the best tarts are made the day before.

Ingredients

Pastry

1batch sweet shortcrustShortcrust and Flaky Pastry, or 320 g store-bought sweet shortcrust
1egg white (about 30 g), lightly beatenfor sealing

Filling

4unwaxed lemonszest of 2, juice of all 4 (you need 150 ml)
5large eggs (about 250 g without shells)
175 gsuperfine (caster) sugar (¾ cup + 2 tbsp)
150 mlheavy (double) cream (⅔ cup)
powdered (icing) sugarfor dusting, optional

Diet: Vegetarian
Allergens: gluten, egg, milk
Origin: France

Method

Line a 23 cm (9 in) loose-bottomed tart pan, 3 cm deep, with the pastry and blind-bake it at 190°C (375°F) as described in Shortcrust and Flaky Pastry. 38 min
While it is still hot from the oven, brush the inside with egg white and return it for 2 minutes to seal. Leave the case in the pan and keep it on a baking sheet. Reduce the oven to 140°C (285°F). 2 min
Finely zest 2 of the lemons, then juice all 4 and measure 150 ml juice.
In a bowl, whisk the eggs and sugar gently until smooth, without making froth. Whisk in the lemon juice and zest, then the cream. Strain through a fine sieve into a jug, pressing on the zest, then skim off any foam from the surface.
Set the baking sheet with the tart case on the oven rack pulled halfway out. Pour in the filling almost to the top, then carefully slide the rack in.
Bake 30–40 minutes, until the filling is just set at the edge but the center still has a slight, even wobble, like a jelly, and reads about 75°C (167°F). 35 min
Cool on a rack for 1 hour, then chill for at least 3 hours. Trim the pastry edge if needed, remove from the pan and dust with powdered sugar just before serving. Slice with a hot, dry knife. 4 h

Why it works

The filling is a custard set by egg proteins, and like any custard it turns rubbery and weeps if overheated, so a low oven and pulling it while it still wobbles give a silky texture. Lemon's acidity actually helps: it lowers the temperature at which the eggs set. Straining removes zest and stringy egg, and sealing the hot crust with egg white stops the liquid soaking in before it sets.

Common mistakes

Whisking in air, which leaves bubbles on the surface. Whisk gently and skim.
Baking until firm; it cracks and tastes eggy. The wobble is right.
A cracked or unsealed pastry case that leaks filling. Patch cracks with raw pastry before the egg white wash.

Variations

Lime tart: Use 6–7 limes for 150 ml juice and the zest of 3.
Brûléed top: Sprinkle the chilled tart with a thin layer of sugar and caramelize with a kitchen torch just before serving.

Make ahead and storage

Best made the day before; keeps 3 days in the fridge. The blind-baked case keeps 2 days in an airtight container.

Notes

Fan oven: 170°C (340°F) for the pastry, 120°C (250°F) for the filling.