What is the best thing to use for my treble clef and letters for my cake?

I have just found an interest in baking cakes and plan to use it as a profession. My best friend wants me to make a cake for her birthday and since she is a very good singer i decided to do a music chart with a treble clef and letters. Instead of E G B D F though i am going to spell out Happy Birthday Sally*. I am doing a whipped icing for the icing, but i was wondering what i could make the treble clef and letters out of. I dont want to simply use icing and write it by hand. I would like this to look very professional. Any advice will be greatly appreciated !