Crispy chocolate icing

[blamethecat]

Trying to find a way to make crispy chocolate icing for a cake but not sure what to do. Definitely don't want buttercream but more like glace icing but crunchier. Any ideas ?

I'm not much of a baker but my Gran was and she used to make a lovely chocolate cake finished with a crisp layer of chocolate on top. I think she basically melted some better quality cooking chocolate in a Bain Marie and poured it over the sponge before smoothing it with a palate knife? Once it had cooled it was like a chocolate shell and cracked when you cut it.
P.S. I realise this is probably too late now but may be worth a try next time.