First, melt the jam with the Armagnac in a small saucepan, stirring until all the lumps have dissolved. Now, using a brush, coat the surface of the cake quite generously with it.
Take the marzipan and roll it out on a surface lightly dusted with icing sugar and cut out an 8 inch (20 cm) round or square (depending on your cake tin), then place this over the top of the cake.
Repeat with the icing and place this over the marzipan.
Using the cutter, cut out a shooting star from the remaining rolled-out icing, dampen one side of it with cold water and then place this side on top of the cake. Decorate the edges of the cake and the star with silver balls.