This breaks the juice sacs in the lemon, which makes it easier to extract the juice.
The addition of the eggs provides creaminess because the eggs encourage the formation of an emulsion. They stabilise the fat in the lemon base provided by the butter. Cooking will then coagulate the egg proteins, making the curd more viscous.
Cooking
Incorporating the butter
MAKES 550 G CURD
2 g leaf gelatine
200 g egg (4 eggs)
140 g lemon juice plus their zest
(about 7 lemons)
160 g caster sugar
80 g butter
1 Hydrate the gelatine in cold water.
2 Whisk the egg lightly in a stainless-steel bowl.
3 Put the lemon juice and zest and the sugar in a saucepan. Whisk a little to dissolve the sugar and place over heat.
4 When the mixture boils, remove from the heat and pour over the egg while whisking energetically so the egg doesn’t cook.
5 Pour back into the saucepan, return to the heat and continue to whisk. As soon as it starts to boil, remove from the heat. Whisk in the butter and the drained gelatine, then blend for 2–3 minutes using a hand-held blender.