For the raspberry-poppy seed cake in a jar, separate the eggs, whisk the egg yolks with the soft butter until foamy. In the meantime, beat the egg whites with the sugar until stiff, stir in the egg yolks, flour, poppy seeds, cornflour and melted chocolate, then carefully fold in the beaten egg whites and raspberries.
Fill the jars halfway with the cake mixture and bake the raspberry-poppy seed cake in the jar in a preheated oven at 175 °C for 30 to 40 minutes.