Soak gelatine in cold water. Wash and clean the strawberries. Dice 250 g strawberries. Puree remaining strawberries and 80 g sugar. Put 2 tablespoons of puree in a freezer bag.
Dissolve gelatine dripping wet at low heat. Mix with strawberry puree, strawberries and lemon peel. Stir in buttermilk and chill. As soon as the mixture begins to gel, fold in sour cream. Cut the lady fingers in half crosswise and place them in a flat form with the cut side down. Pour in strawberry cream, smooth it down and let it get firm. Mix crème fraîche, lemon juice and remaining sugar. Pour over the cream. Cut off a small corner of the freezer bag.
Pour in strawberry cream, smooth it down and let it get firm. Mix crème fraîche, lemon juice and remaining sugar. Pour over the cream. Cut off a small corner of the freezer bag. Spray strawberry puree spirally onto the cream. Decorate with lemon balm
(4 persons). (6 people)