Gluten-free "Oreos"

So my second attempt at gluten-free baking was "oreos". I used this recipe for the cookies and this one for the filling. I made half with vanilla filling and half with pink peppermint filling (adding about 1/2 tsp peppermint extract to half of the frosting). I noticed the same thing with the grittiness of the brown rice, so I'm thinking in the future I think I'll just try using white rice flour. The cookies weren't too bad. The xanthan gum seemed to leave a bit of a metallic sort of aftertaste, but once the cookies were filled, I really didn't notice it. They're nice and crisp wafers, and I think they'd be great for a chocolate crumb crust for a gluten-free cheesecake.