I need help with a design for a birthday cake, only requirements is pink and purple flowers and 2 tiers. The theme of the party is Barbie, but the mother only wants flowers on the cake. BC frosting, not fondant TIA

You could do one pink tier with purple flowers and one purple tier with pink flowers.

Here are some ideas from the gallery, just use your colors. Any that are fondant you could do with buttercream instead.

http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1399168

http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1398146

http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1394173

http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1390104


Are you able to use fondant accents? If so, here are a few pretty ideas. (Maybe you can figure out how to do them with buttercream. I'm not that good though!)
http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1393195

http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1391146

I would make all of my flowers in royal icing, then add leaves etc. in BC.

I think this cake is all about color. I would do a pale pink cake or pale yellow and then add all of the bright colored flowers to it and it would pop. If she only wants pink and purple, then I would do different shades of them.

HTH

Thanks for the ideas. I have such a hard time with originality and creating designs.