1.Preheat oven to moderate 180°C (160°C fan-forced). Grease and line three deep 20cm-round cake pans. Make cake according to directions on packet, divide mixture among pans, bake in moderate oven about 40 minutes. Stand cakes in pans 5 minutes; turn onto wire racks to cool.
2.Using small serrated knife, trim cake tops to make more rounded, as shown. Brush jam all over cakes.
3.On surface dusted with icing sugar, knead icing until smooth, knead pink colouring into ¹/³ of the icing. Reserve a walnut-sized amount for balloon end, enclose in plastic wrap.
4.Using rolling pin, roll remaining pink icing into circle large enough to cover one cake. Using rolling pin, lift icing over one cake, using sharp-pointed knife, neatly trim excess icing. Position cake on board.
5.Using hands dusted with icing sugar, gently mould icing into balloon shape.
6.On surface dusted with icing sugar, make balloon end from reserved pink icing. Using toothpick or skewer, make creases in balloon end. Using toothpick, push end of ribbon into balloon end, attach to cake with a tiny dab of water.
7.Repeat with remaining cakes, icing, colourings and ribbons.
On a surface dusted with icing sugar, mould the balloon end from the reserved icing Dust your hands with icing sugar then gently mould the icing into a balloon shape When icing is large enough to cover the cake, carefully lift icing over cake using a rolling pin Using a toothpick or skewer, make small creases in the underside of the balloon end Using a small serrated knife, trim the tops of the cakes to make more rounded