Put the raspberries
and sugar in a blender or food processor and process
until smooth.
Reserving 1 tablespoon of the
crème
fraiche for decorating, put the vanilla essence and
crème fraiche in a bowl and stir in the raspberry
mixture.
Whisk the egg whites in a separate bowl
until stiff peaks form. Gently fold the egg whites
into the raspberry mixture using a metal spoon,
until fully combined.
Spoon the raspberry fool into
individual serving dishes and chill for at least 1
hour. Decorate with the reserved
crème fraiche.