To a medium bowl add the brown rice flour and quinoa flour. Pour in the boiling hot water and stir it into the flour to make a stiff paste. Cool to lukewarm.
In a small bowl add the orange juice and whisk in the psyllium husk. Let this sit to form a gel while mixing the remaining ingredients.
Add the coconut oil to the flour paste and stir in the flax seeds. Mix well before adding the sorghum flour, tapioca starch, brown sugar, and salt. Combine with a spoon, until there is no loose flour
Add the psyllium gel to the flour mix and combine all the ingredients well.
Form the pastry dough into a ball, place it into a container with a sealed lid and refrigerate the dough overnight, or for at least 20 minutes before rolling it out.
Cut the dough in half (about 246 g each) and place each piece on a sheet of parchment paper. Roll out the first piece of dough into an 8 x 10 inch (20 x 25 cm) sized rectangle. Place the dough, still on the parchment paper, onto a baking sheet. Chill the dough for about 20 minutes. This will be the base.
On a second piece of parchment paper, roll out the other piece of dough, which will be the top of the pop tart. Roll the dough out into the same rectangular shape as the base. Chill the dough to make it easier to handle and shape.