I used a white chocolate mud cake recipe (from planet cake) for the base, having previously tried to use a normal victoria sponge and it sinking under the weight when I tried to carve it. I bake a square cake, which I sliced in half, before stacking together with vanilla buttercream icing. I then wrapped the cake in clingfilm and stuck it in the freezer overnight.
The next step was to cover it in sugarpaste- before doing this I used a hot knife to get the buttercream as smooth as possible. I used 2 x 250g blocks of amethyst purple regalice (purchased from www.cakecraftstore.co.uk). I rolled it out and cut a rectangular strip the width of the cake to begin with, with two semi circles cut out of each side, and I then placed this over the cake from front to back. The next job was to cut rectangles for the sides, which i then curved the edges of. I made these slightly bigger than the space left so that they would overlap the section already on the cake. I also covered a cake board with white regalice.
The next steps involved cutting square pockets for the front of the bag, which have slightly smaller squares on top as little flaps. A small ball squashed flat then forms the button/buckle. These are 'painted' with antique silver sugarflair edible lustre. I also cut a long thing strip for the zip and made a little zip pull using a small ball and a small rectangle- all again painted with lustre. These were all added with a little bit of water brushed on to the back. You will see that the regalice is a bit wet here- it soon dries up though. I used a 'stitching' tool to create the look at stitches on the pocket and and the edges were the front and side sections meet.
After this, I faffed about with decorating the base with numbers and little balls of white icing to put my candles into. I also used a lettering set to create an 'embossed' message, which I then iced pink sparkly writing icing .
The last thing to do is the handles- I left the whole cake in the fridge overnight and did the handles on the morning of my party. They are made with 8mm flexible tubing that I found on ebay. The purple icing is simply wrapped around the tube and then I used dowels pushed inside the tube to attach these to the top of the cake. This is definitely the hardest part of the making the cake- it's hard to get them smooth enough and you might need to use something to prop them up while you wait for them to solidify (I had to do this with the back handle- you can see it's trying to fall backwards in the 1st photo below!)