Whip the cream together with a few table spoons of icing sugar. Whip it to hard peaks (not soft)
Make the Creme patisserie: 1 sachet of kagecreme powder mixed with 500ml whole milk. Whisk well and chill for 15 minutes in fridge before using.
To assemble the cake:
Remove packaging from sponge cake layers. On your chosen tray, add first layer of sponge. Add on top a thin layer of raspberry jam, then add half the crème patisserie evenly all over. Add sponge layer and repeat. Add top lid.
On the top sponge layer, carefully add the whipped cream in a “dome” shape – you will need to use a spatula here to get it quite smooth all over. You’re looking for around 3-4 cm “top” on the cake.
Once you are happy with the whipped cream, add the green lid. This is the tricky bit. Carefully unwrap the lid and line it up to go on the cake. You only have one shot at this as it is hard to move. Once placed, carefully press the sides down around the cake. Some cream may seep out, so use a spoon to wipe any excess so the lid will fit snugly
Use a piping nozzle and any leftover whipped cream to pipe rosettes of cream around the edge to hide the bottom of the marzipan and any folds.
To make a rose: add few drops of food colouring to the marzipan – add icing sugar if it gets too sticky. Roll out a 1 mm thick piece, 2 cm wide and around 10 cm long. Roll it up loosely, nip the bottom together, spread the leaves a bit and voila: A marzipan rose to the top of your cake