I've been wanting to try this since I heard about it.... but I don't make it to McD's that regularly - just when the kids talk me into it.
A while ago I finally had it. McDonald's haupia pie. This appears to be a local addition to their menu. What is haupia? It's a coconut pudding. You can buy haupia cake in stores, such as Safeway or Zippys.
What did I think? It was crispy on the outside with a hot coconut pudding filling. Not too sweet, the flavor was good, but I wish it had had more texture, maybe chunks or something in it - though I'm not sure what that would be like either.
I'm betting you can only get this in Hawaii. If you see it elsewhere, let me know! I'm curious.