Line the bottom of a springform pan (26 cm Ø) with baking paper. Melt 50 g butter in a small pot, let it cool down lukewarm. Separate the eggs. Beat the egg white with the whisk of the hand mixer until stiff, add 175 g sugar and 1 pinch of salt. Stir in egg yolks. Mix flour, baking powder and almonds, fold carefully into the egg cream. Fill the mixture into the springform pan and smooth it down. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 25-30 minutes, let cool down on a cake rack
Caramelise 200 g sugar in a pan until golden brown. Remove from heat, add 25 g butter and 1 pinch of salt. When the butter has melted, stir in the nut kernel mixture. Place the caramel nuts on a piece of aluminium foil lightly coated with oil and spread immediately. Pull some of the nut kernels to the edge and remove them from the remaining caramel mixture. Let it cool down. Coarsely chop the caramel nuts, except for those on the edge. Grind finely in the universal chopper, put approx. 2 tbsp. aside for decorating
Remove the base from the pan and remove the baking paper. Cut the base twice horizontally. Place a cake ring around the lower cake base. Mix vanillin sugar and cream thickener. Whip the cream until stiff, allowing the cream firming mixture to trickle in. Pour approx. 1/4 of the cream into a piping bag with a large perforated spout, refrigerate. Fold the ground caramel nuts and 5 tbsp. rum into the remaining cream.
Stir plum puree until smooth. Spread about half of the plum puree on the bottom layer and spread. Spread about 1/3 of the cream on top. Place the second base on top and sprinkle with 2 tbsp. rum. Spread the rest of the plum puree on top. Spread 1/3 of the cream on top. Place the upper cake layer on top and sprinkle with 2 tbsp. rum
Remove the cake from the ring and spread with the remaining cream. Spray the cream as a dab on the edge. Chill for about 2 hours. Just before serving, decorate with whole caramel nuts and sprinkle with ground brittle
waiting time approx. 3 hours