Mix soft butter, sugar and whole eggs together in a bowl until smooth.
Add the lemon juice and cook over a saucepan of simmering water. Whisk continuously until the lemon curd thickens.
Drain the gelatine and add to mixture. When the mixture is cold, pour in a non-stick tray at least 3cm deep. Place in the freezer.
When the curd is thick, remove it from the freezer and cut into slices.
Mix all ingredients together until you have a smooth dough. Wrap and keep in fridge for at least 2 hours.
After 2 hours, roll the dough until 5mm thick. Cut the layer in a rectangle of 10x4cm and cook in 180°C oven for 15 minutes. Leave to cool in the oven.
Whip the egg whites and slowly add the caster sugar until soft peaks form.
Put the mixture in a bowl and, with a spatula, incorporate the icing sugar. Work until smooth. Place in a piping bag.
Position the piece of lemon curd above the rectangle of sable breton.
With a piping bag make 5-6 dollops of meringue on one side and flame with blowtorch.
Decorate with lemon balm leaves, gold leaf, orange segments and a scoop of lemon sorbet.