method
1. Spoon the lemon curd into a bowl. Whip the cream until it will hold a soft peak, then fold it into the lemon curd.
2. Add a pinch of salt to the egg white and whisk until it forms soft peaks, then carefully fold it into the lemon mixture.
3. Spoon into 4 serving dishes and chill for as long as possible.
4. Just before serving, crush the biscuit and scatter the crumbs over the top of each dessert to give them a sweet crunch.
