1. First, let's make the sponge: Preheat the oven up to 175° C. Line the base of a 20 cm round baking mould with baking parchment and grease it.

2. Put the eggs and sugar into a large bowl and mix them with a hand mixer, whisk together until the mixture is foamy and rather pale. Add the potato starch, flour and baking powder into an extra bowl, mix swiftly and then mix it into the egg mixture.

3. Pour the mixture into the lined tin and bake for 40 minutes. Set aside to cool and let it cool completely on a wire rack.

4. For the vanilla custard: Cut the vanilla pods open lengthways and scrape out the seeds. Mix the seeds with the sugar to get an evenly spread vanilla sugar.

5. Meanwhile, pour the milk into a pot, add the cut open vanilla pods heat up the milk. Remove from the heat. Whisk the egg yolks, vanilla sugar and cornstarch together in a large bowl with an electrical mixer.

6. Remove the vanilla pod from the warm milk and stir the warm milk slowly into the egg mixture. Now pour the mixture back into the pot and cook over a low heat for 4-5 minutes, while thoroughly whisking until the mixture thickens up.

7. Remove the custard from the stove and whisk in the butter until melted and fully incorporated. Either let cool off completely in the pot or transfer it to a bowl and cover the surface with transparent foil to prevent a skin forming. Set aside to chill in the fridge.

8. Now you can prepare the rose: Roll out the pink marzipan onto a flat surface and cut out 6 little round pieces using a cookie cutter or in my case an eggcup in 2-3 cm in diameter (these will form the petals).

9. Bend and curl the edges of the petals, to make them look more realistic. Place these pieces slightly apart on top of each other and start rolling until you get a beautiful rose (check the video).

10. Whip up the 1000 g double cream until whipped and stiff.

11. Now let's assemble the cake. Cut the cake horizontally into three even layers. Place one of the sponges onto a serving plate. Spread a thin layer of custard over the base of the first sponge 8about half the mixture) and add the frozen berries on top. Place the second layer of sponge on top.

12. Mix about 400 g of the whipped cream with the leftover custard and spread onto the second layer. Place the third layer on the little cake tower and frost the whole cake with the rest of the whipped cream forming a dome.

13. Set aside in the fridge for an hour (if you have the time). Lift the marzipan cover up over the cake and using your hands, shape the marzipan around the sides of the cake to get a smooth finish. Trim any excess.

14. Top the cake with your handmade marzipan rose and dust it with powdered sugar. Enjoy!