How long can I store frozen cupcakes which have been thawed/brought to room temperature? Or should I thaw them just before I need them? These are chocolate cupcakes with ganache...

Thanks!

Cupcakes thaw really quickly, just take them out a little before you need them.  You can even ice them while still frozen and they thaw as you are working.

The problem is I have already thawed it and the customer suddenly decided to pick it up a day later...

Your initial question makes it sound like they are still frozen.  If they are already thawed and ready to go, I wouldn't freeze them just until tomorrow. 

AOh hahha now that I read them again it does sound like they are still frozen...

I just tried one of them and they were still fine. Phew!

Thanks! :)

good, keep in mind that if the customer changes their plans, the problem is on them.  Next time really try to get them to stick with the original  pick up plan, then you don't have to figure out what to do.