Soak gelatine in cold water. Stir yoghurt, lime zest and juice, 4 tbsp. sugar and vanillin sugar until smooth. Squeeze the gelatine and dissolve at low heat. First stir in 3 tbsp. yoghurt, then stir into the remaining yoghurt. Cool until the cream begins to gel
Whip the cream until stiff and fold into the yoghurt. Chill for at least 4 hours
Select the raspberries, wash if necessary (defrost frozen raspberries). Puree berries, except for a few for decoration, and 2 tablespoons of sugar and pass through a sieve
Cut off the yoghurt mousse with 2 moistened tablespoons of cam and place on 4 plates. Spread raspberry puree around them. Decorate with remaining raspberries, lime slices and lemon balm