You can do it! You can also use royal icing and candy melts, too. There are some great ones here on this site. I was JUST looking through a book just now with initials on cakes! 
You can also use gumpaste, too.
Good luck.
Angie
Edited for bad spelling!!!!
Angie, it's funny (not ha-ha funny) that this is being brought up, because I have a order for 75 cupcakes and the lady wants the initial standing up on the cupcake. I went to Micheals today and purchased blue candy melts to practice with. I wasn't sure if it would work or not, I keep haveing visions of the candy melting and running off the cupcake. Thanks
Unless you are going to be outside in very hot weather the candy melts are not going to melt.
Thanks thats what I was needing to hear, it will be inside a church
Okay here is the end result of my Bridal shower cupcakes. I had so much fun doing these, if I had my choice I would do cupcakes all day long. A very special THANK YOU to Nati for help and advice on these. I delivered them to the church this evening and the ladies were very pleased with them
Great cupcakes and intitals! so simple, yet elegant and fun!
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