What to replace marzipan with when icing a fruitcake

[TheSkiingGardener]

DB is allergic to nuts so I need to ice a fruitcake without using marzipan. Is there a good alternative. I want to use royal icing to get that nice finish.

Thanks

You can use regal ice with out marzipan, so I guess you could try a thin layer of that then royal icing.