Beat butter at room temperature with honey. Add the yolks and beat again.
Add the poppy seeds, nuts, and vanilla sugar.
Stir. Beat the whites in a separate bowl and add to the poppy mixture.
Spread the cake form with paper.
Pour the dough into the mold and bake in the preheated oven at 180g. 35 minutes.
Cut the plum into nice pieces.
Cool the cake base with jam.
Put the plum on the jam.
Prepare the jelly for the cake according to the instructions and, when the jelly begins to harden slightly, apply it to the plum.
Put the cake in the refrigerator overnight.