Soften gelatine in water and dissolve over boiling water.
Place sugar and extra water in saucepan, stir over low heat until sugar has dissolved.
Simmer without stirring until syrup is caramel colour.
Heat milk in saucepan; when hot, add hot caramel and continue stirring over low heat until caramel is dissolved.
Remove from heat.
Beat egg yolks with extra milk, add to caramel; mix thoroughly.
Add softened gelatine and vanilla.
Refrigerate until mixture begins to set.
Fold in stiffly beaten egg-whites and whipped cream.
Pour into lightly oiled 2 1/2-pint mould.