I frost my carrot cake with cream cheese buttercream. I use Rose’s recipe and replace the white chocolate with xxx sugar. She suggests this in her Heavenly Cakes book to use 1/2 cup or so. This is a softer type of buttercream and is a little harder to pipe with. If I need alot of piping and decorating, I use IMBC to do that with. I doubles and triples well and if it’s a hot day, cut back on the butter and adjust the flavoring with vanilla or whatever you want. It hardens in the fridge like IMBC and will smooth well. If your cake is cold (do a light pre frost and put in the fridge for about a 1/2 hour, the second coats goes on like a dream. If you want to do some light decorating with it, fill a cake pan with water, freeze it, and lay you piping bag on that. (read that somewhere and it works like a charm). I’ts not that you can’t pipe with it, it just softens quickly and doesn’t hold up well for alot of fine detail piping. It’s yummy and people will love it.