Grease a springform pan (26 cm Ø; at least 8 cm high). Put the rusk into a freezer bag and crumble it coarsely with a dough roll. Spread half the rusk in the form. Wash, halve and stone the plums and cut them in half lengthwise. Melt the fat at low heat. Mix sugar, cinnamon and almonds.
Sprinkle half on the rusk. Pour half of the liquid fat over it, cover with half of the plums. Add the rest of the rusk, then the remaining almond-sugar-mixture. Pour the rest of the fat on top. Spread the rest of the plums on top. Mix sour cream, eggs, icing sugar and salt. Gradually pour over the cake. Bake in the preheated oven (electric cooker: 175 ° C/ convection oven: 150 °C/ gas: level 2) for about 1 hour. Leave to cool completely in the mould. Roast the flaked almonds in a pan without fat. Heat the jam and pass through a sieve. Spread the cake rim with it.
Gradually pour over the cake. Bake in the preheated oven (electric cooker: 175 ° C/ convection oven: 150 °C/ gas: level 2) for about 1 hour. Leave to cool completely in the mould. Roast the flaked almonds in a pan without fat. Heat the jam and pass through a sieve. Spread the cake rim with it. Press the flaked almonds on it. Decorate the cake with lemon balm
Waiting time approx. 3 hours.