Pre-heat oven at 200 C / 400 F
Mix psyllium husk and water and let rest for a a couple minutes until it becomes gelatinous
In a jar or mug mix water and olive oil (for the dough)
In a large bowl add brown rice flour, white rice flour, potato starch, baking powder, table salt and mix well
Add psyllium husk gel and olive-water mix to the dry ingredients and incorporate them as much as possible, using a fork or spoon
When you get a crumbly mixture, move it to a worktop and work the dough with your hands, pressing and kneading for a few minutes, until you obtain a firm and smooth dough ball (if the dough is too wet and sticks to your hands, add 1-2 tablespoons of white rice flour and keep kneading until it's smooth)
Generously grease the bottom and sides of a baking pan
Place the dough on in the baking pan and spread it to the sides pushing it down with you hands
Using you fingers create dimples on the dough surface
Sprinkle the surface with oil-water emulsion and coarse salt
Bake in pre-heated oven for ca. 40 minutes or until the crust is golden brown
Let cool down for 15 minutes before removing from pan and slicing.