Lemon meringue cake

A lemon meringue cake is a sharp filling under a sweet meringue. The common failures are soggy meringue, runny curd and a cake that weeps. One cause: curd is moisture, and meringue drinks it.

What it is made of

Top to bottom:

Two sponges, two layers of curd, meringue on top.

An honest note: the classic is a lemon meringue pie, with a shortcrust shell, curd and a soft meringue browned with a torch. Here sponges replace the pastry and the meringue is a baked layer, not a curly foam. The layer is crisp rather than soft, though it also soaks up the curd faster.

Order of work

Curd (the day before): lemon juice and zest, sugar, eggs, butter. Cook over low heat or a water bath, stirring constantly, until thick: egg proteins set at roughly 80 to 85 °C and the mixture thickens. Do not let it boil. Strain through a sieve and cool under film pressed against the surface. Cold curd is thicker.

Meringue: a glass or metal bowl wiped with vinegar. Whites at about 21 °C. Start on low speed with a pinch of salt, add fine sugar in portions until fully dissolved (rub between your fingers). A little cornflour at the end. Bake at about 100 to 120 °C for 1 to 1.5 hours until dry; below 100 °C stays whiter. Cool in the oven with the door ajar.

Sponges: vanilla, baked and cooled ahead; chilled 4 to 10 hours they slice cleanly.

Assembly (a few hours before serving):

1. Sponge. Pipe a thin ring of thicker curd around the edge as a dam, or use a ring mould.
2. Curd inside, thin. The next sponge.
3. A second layer of curd.
4. The meringue disc on top.

Do not cover with film: it traps moisture and the meringue goes soft. Serve within a few hours and keep fridge time minimal.

What can go wrong

• Runny curd. It did not reach 80 to 85 °C.
• Grainy curd. Overheated and the eggs scrambled. Strain it.
• Sticky meringue. Sugar not dissolved or not dried long enough.
• Meringue went soft. Assembled too early or covered with film.

The verdict

Time decides this cake: cold, thick curd, dry meringue, late assembly.