Soak gelatine in cold water.
Beat vanilla pulp, egg yolks, eggs, granulated sugar, vanilla sugar, rum and salt over steam, first hot, then cold, until fluffy.
Squeeze gelatine, heat in about 50 ml water and add. Gently stir in whipped cream.
Pour vanilla cream into an approx. 30 x 20 cm rectangular mold and chill thoroughly.
Roll out puff pastry on a floured work surface to the thickness of the back of a knife and cut into 2 pastry sheets, each 30 x 20 cm. Place on a baking sheet lined with baking paper, poke (prick) several times with a fork and let rest.
Bake in a preheated oven at 180 °C for 15-20 minutes and let cool. Spread dough sheets on the smooth side with warmed apricot jam.
Heat fondant to about 40 °C and thinly glaze one pastry sheet with it. Allow to dry at about 60 °C.
For the cream slices, turn the cream out of the mold directly onto the unglazed pastry sheet, place glazed top on top and divide into slices.
For the sake of simplicity, you can also put the already baked pastry sheet in the mold (in this case, preferably in a frame mold), pour in the cream and let it set. Then simply remove the frame and place the second glazed sheet of dough.