I'm really picky about my cupcakes.
Anyway, I've had Retro Bakery cupcakes more than once, lots of my friends love them for catering and of course, Kari's really cool about supporting the arts and being involved locally.
So: frosting is buttercream, and sometimes is covered in a chocolate or other flavor shell. Really good, some unusual flavors which are fun. I like the mint one, but being traditionalist I usually get chocolate.
The problem is that I'm not super crazy about the cake here, or the construction. The frosting is piled up so high that it is hard for me to take a bite of both frosting AND cake without smashing it all over my glasses or nose.
Still, they're pretty awesome cupcakes and I would recommend them, I'm just not entirely sure why people go crazy over them. Though the owner is a wonderful person. It is the best bakery on this side of town, though.