Hi I'm doing a cake for a local kids charity next weekend with a mid winter christmas theme.  My plan is to do a large spiral cake in a snowy theme with penguins sliding down etc etc and I was planning on covering it with Royal Icing swirled about to look like snow.

This is where I'm stuck as I'm making it in pound cake and had planned on filling and coating with SMBC first then covering with RI but now I'm doubting myself and thinking that the fats might react with the RI etc etc and cause issues???

Any advice would be appreciated I don't really want to have to cover it with fondant first as that's going to make 3 layers of icing and would prefer not to use ganache as I find kids don't go for that here in NZ as it's too rich for them.

TIA Andi 

my suggestion is just to add an idea to the idea pot--tap powdered sugar out of a sieve for a nice snowy effect-- it can help cover a multitude of sins as well--

i mean i've piped royal icing dots onto smbc without any problem and they've held for ages on a dummy-- i can't remember actually icing completely over smbc but it should work-- but it's not gonna be as pleasant to serve and eat maybe--

maybe just make some drifts and accents with the royal and solidify the visual effect with the powdered sugar 'snow' --

if i was going to do this--i'd ice in the smbc which makes it slightly yellow right--so i'd airbrush super light blue-- then i'd do the powdered sugar snow-- so that way it would appear icey where it wasn't covered with snow --

or maybe try some american buttercream

Thanks for the advice, I had thought about using icing sugar but then thought it would probably melt wouldn't it?

Hmmmm feeling very confused now lol, hate it when I had a great plan in my head and then it all falls apart 

I had thought maybe about doing a very thin layer of fondant over the whole thing then RI?  It used to behow all christmas cakes were done but then they were always fruit cakes with marzipan.

Anyone else have any thoughts???

Thanks that looks great, unfortunately I'm in New Zealand where we are depressingly limited in supplies and don't get anything out of the ordinary or exciting lol