Lightly oil a rectangular (approx. 20 x 28 cm) or a round tart (26 cm Ø) with a removable base at the bottom
Coarsely chop the chocolate coating and melt in a hot water bath. Cool down a little. Coarsely chop the lady fingers and nuts. Stir into the liquid chocolate coating. Spread as a base in the mould, press on. Chill for about 30 minutes.
Soak gelatine in cold water. Wash, halve, stone and slice the nectarines
Mix yoghurt, lemon juice and sugar. Squeeze the gelatine, dissolve at low heat. Stir in 4 tablespoons of yoghurt, then stir into the remaining yoghurt. Chill for about 15 minutes until it starts to gel
Slice the nectarines, up to about 24 for decoration, and spread them on the chocolate base. Whip the cream until stiff, fold into the yoghurt. Spread lightly on the nectarines. Chill for about 3 hours. Decorate with the rest of the nectarines and lemon balm