This recipe is adapted from the River Cottage Gluten-Free cookbook. A bourbon biscuit press can be bought from Amazon.
The flour mix works well, but I think you could substitute the gluten-free flour mix fairly easily. Also, the amount of cocoa seems to be considered excessive by some, so that could be reduced in the biscuit dough, by maybe up to half).
Given that the end result is two pieces sandwiched together, it is very important to roll them out thin. This recipe should make about 15-20 biscuits.