Grease the springform pan (26 cm Ø). Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Coarsely chop nuts and almonds. Coarsely chop chocolate. Melt with the butter in a hot water bath.
Leave to cool at lukewarm.
Mix flour, sugar, vanilla sugar and 1 pinch of salt. Whisk eggs and stir into the melted chocolate. Add to the flour mixture and stir everything briefly with the whisks of the mixer until smooth.
Put the dough into the mould and smooth it down. Spread the nut mixture on top and press down a little. Sprinkle with brown sugar and bake in a hot oven for about 20 minutes.
Warm the jam and pass through a fine sieve. Then spread in splotches on the nuts and bake the cake for 20-25 minutes. Remove from the edge of the pan with a knife. Leave to cool in the mould.