Knead 150 g flour, fat, 75 g sugar, salt, egg yolk and 2 tablespoons of ice-cold water into a smooth dough. Cover and leave to rest in a cool place for about 30 minutes. Roll out the short pastry on a springform pan (26 cm Ø) and prick several times with a fork.
Place the edge of the springform pan around the bottom. Bake in the preheated oven (electric: 200°C/ gas: level 3) for 12-15 minutes. In the meantime, separate the eggs. Beat the egg white and 2 tablespoons of water until stiff.
Add 75 g sugar and vanillin sugar and stir in the egg yolk. Mix the remaining flour, starch and baking powder, sieve onto the egg mixture and fold in. Spread on the pre-baked shortcrust pastry and bake in the preheated oven (electric cooker: 200°C/ gas: level 3) for 12-15 minutes.
Remove and let it cool down. Spread the raspberry jelly on the sponge cake base. Wash two limes and grate the peel. Squeeze the limes. Soak the gelatine in cold water. Mix milk, coconut cream, sour cream, lime zest and the remaining sugar.
Squeeze the gelatine, dissolve it and stir in the lime juice bit by bit. Gradually stir the gelatine and lime juice into the coconut sour cream and refrigerate. Whip the cream until stiff and fold in as soon as the coconut sour cream begins to set.
Spread the cream on the sponge cake and refrigerate for about 3 hours. Wash the remaining limes and cut into thin slices. Remove the cake from the springform pan and serve with lime slices, coconut chips and, if desired, lemon balm.