Bake the Sponge Cake (20 min):
Preheat oven to 350°F (175°C). Grease and line two 8-inch round pans.
Beat eggs and sugar until fluffy and pale. Gently fold in sifted flour and baking powder. Add vanilla.
Divide into pans and bake for 18–20 minutes. Cool completely.

Prepare the Pastry Cream (10 min + chill):
In a saucepan, heat milk to a simmer. In a bowl, whisk yolks, sugar, and cornstarch.
Slowly pour hot milk into the yolk mixture, whisking constantly. Return to heat, stirring until thick.
Stir in vanilla. Let cool in the fridge with plastic wrap touching the surface.

Whip the Cream (5 min):
Beat heavy cream and powdered sugar until stiff peaks form. Chill until ready to use.

Assemble the Cake (15 min):
Place one sponge layer on a cake board. Spread raspberry jam, then a layer of pastry cream.
Add a mound of whipped cream in the center and cover with the second cake layer.
Use remaining whipped cream to shape a dome. Smooth it out.

Decorate (5 min):
Roll out the marzipan into a thin sheet. Carefully drape it over the cake dome.
Trim the edges and dust the top with powdered sugar. Add a fondant rose or edible pearls if desired.