Soak gelatine in cold water. Mix buttermilk, lemon juice, sugar and vanillin sugar. Squeeze the gelatine and dissolve at low heat. Add 2 tablespoons of buttermilk to the gelatine and stir.
Stir into the remaining buttermilk and chill. Meanwhile drain the peaches and cut them into slices except for two halves. Line 4 dessert glasses with them. Whip the cream until stiff. As soon as the buttermilk begins to set, fold in the cream, except for a little for decoration.
Pour into the prepared glasses and leave to set in the refrigerator for about 2 hours. Pour the rest of the cream into a piping bag with a star-shaped spout and squirt a tuff onto each cream. Cut the remaining peach halves in half and cut them in a fan shape.
Place on the cream, sprinkle with pistachios and serve decorated with melissa as desired.