Preheat the oven to 160°C. Line a 20-22 cm cake tin with baking paper.
Heat the milk with the butter in a small pan.
Separate the eggs.
Add salt, vanilla sugar and half of the icing sugar to the egg whites. Whisk it with a hand mixer on low speed. When it's foamy, add the remaining sugar, turn up the speed and beat until it turns into stiff peaks that stand straight.
Add the egg yolks and continue whisking for 2-3 minutes until the mixture turns white. Sift in the flour gradually and stir thoroughly. Make sure there are no lumps.
Transfer a portion of the batter in a small mixing bowl and stir in the hot buttery milk.
Pour this mixture back into the batter and carefully combine until you have a nice, smooth, foamy batter.
Transfer the batter into the prepared baking tin and drop the tin onto the table 2-3 times so that the bigger bubbles can come to the surface.
Using a skewer, stir the batter (along the bottom of the tin) following a circular, shell-like pattern, to allow the bubbles to disperse nicely in the batter.
Put the tin in the preheated oven and bake for 35 minutes.
Do not open the oven door during baking!.
When the cakes is baked switch off the oven and open the door a little.
After 5 minutes take the tin out of the oven and drop it again on the table three times. Then firmly put it onto a wire rack upside down. Let it cool, then take the cake out of the tin. The baking paper should come off smoothly.
Cut the cake, horizontally into two or three identical sheets.
Spread some buttercream on the top if one or two sheets, then some jam - or just spread jam on it.
Warm some jam with a little water, stir until melted.
Measure the diameter of the top and sides of cake.
Dust the work surface and rolling pin with icing sugar, then roll out the marzipan - the diameter should be larger than the top and sides of the cake. The thickness should be about 3mm.
Brush the glaze over the cake, then cover it with the marzipan sheet. Trim the edges neatly, and smooth the marzipan with your hands or an icing smoother tool.
Brush the surface of marzipan with a little warm water to help the icing stick.
Roll out the fondant icing - again the diameter of the sheet should be larger than the top and sides of the cake. Trim the edges neatly, the smooth the icing with a smoother tool or spatula.
Finally, decorate the cake with fondant cake toppers, suitable for the occasion.