Soak gelatin. Mix the buttermilk, lemon juice, sugar and vanilla sugar together. Squeeze out the gelatine, dissolve it and stir it into some of the buttermilk. Then fold in the remaining buttermilk mixture. Chill to gel.
Cut the peaches into wedges except for 2 halves. Line 4 dessert glasses with it. Whip the cream. When the buttermilk mixture begins to gel, fold in the cream, except for 4 tablespoon. Pour into the prepared glasses and leave to set in the refrigerator for about 2 hours.
Squirt the rest of the cream onto the cream as tuffs. Halve the remaining peach halves and cut into a fan shape. Place on top of the cream and sprinkle with pistachios.