Swiss breakfast or really is eaten as a snack any time of day in Switzerland. The recipe contains fresh fruit, berries and nuts which are laced with whipping cream. All the ingredients are left to stand overnight to allow the ingredients to release their flavours. The whipping cream can be substituted by natural yogurt. Caster sugar is very fine sugar - you can either whirl granulated sugar in a food processor or just add granulated sugar if you don't mind a bit of sugar crunch. I am not sure exactly how many this serves since the recipe did not list servings.