Good substitute for rice flour?

Chiming in as I was searching for this answer last night. After some googling, I ended up using cornstarch in place of the rice flour, in the same amount (1/3 cup). These turned out great. Next time I'm at the store I'll get rice flour so I can compare the texture as I will definitely be making these again.

It’s really just to give a crumbly texture. It’ll be fine without it, just a bit more cake like. Just a warning though, these things are addictive...

I read through the comments, and the author recommended 1/4 cup of AP flour in place of the rice flour for those who can't find it.