Lemon Surprise

1. Put grated rind and juice of lemon into a large bowl.
2. Add condensed milk and egg yolks and mix well.
3. Whisk egg whites until stiff and fold gently into mixture.
4. Cover the base of a trifle dish with a layer of the mixture.
5. Add a layer of sponge and cover with more mixture.
6. Repeat and complete with a thick layer of lemon mixture.
7. Chill for at least 3 hours – preferably overnight.
8. Cover with whipped cream and a grating of chocolate.