Melt the butter and let it cool down. Finely grind the rusks. Put 1 tablespoon of ground rusks aside. Mix remaining rusk and melted butter. Pour into a springform pan (24 cm Ø) coated with oil, press down firmly, chill. In the meantime, soak 10 + 4 sheets of gelatine separately in cold water.
Peel grapefruits so that the white skin is completely removed. Halve one fruit lengthwise and cut into slices. From the remaining fruit, remove fillets from the parting skins with a sharp knife. Mix yoghurt, 200 ml grapefruit juice and sugar so that the sugar is dissolved. Squeeze 10 sheets of gelatine, dissolve lukewarm. Stir 2 tablespoons of yoghurt mass into the gelatine. Stir the mixed gelatine into the rest of the yoghurt mass. Chill until the mass begins to gel. In the meantime, whip cream and vanilla sugar until stiff and fold into the gelling cream. Surround the inner edge of the cake with the halved grapefruit slices. Pour in the cream and smooth it down. Chill for about 2 hours.
Chill until the mass begins to gel. In the meantime, whip cream and vanilla sugar until stiff and fold into the gelling cream. Surround the inner edge of the cake with the halved grapefruit slices. Pour in the cream and smooth it down. Chill for about 2 hours. Heat 250 ml of juice. Squeeze out 4 sheets of gelatine and dissolve in it. Pour into a cold rinsed mould and leave to set for approx. 1 1/2 hours. Remove the cake from the rim of the springform pan. Cut the jelly into triangles. Decorate the cake with grapefruit fillets, jelly corners and candied violets. Sprinkle with remaining ground rusk
Squeeze out 4 sheets of gelatine and dissolve in it. Pour into a cold rinsed mould and leave to set for approx. 1 1/2 hours. Remove the cake from the rim of the springform pan. Cut the jelly into triangles. Decorate the cake with grapefruit fillets, jelly corners and candied violets. Sprinkle with remaining ground rusk
Attention: Picture 2 without candied violets