Blend the dry ingredients in a bowl. Add the butter and using an electric mixer, mix till the mixture is sandy. Add the flax seed powder-water mixture and mix till combined. Form the dough into a disk, wrap with clingfilm or parchment and refrigerate for at least 1 hour and up to 3 days.
When ready to bake, grease a cookie sheet or line it with parchment paper or a silicon mat. Roll out the dough to 1/8-inch thickness, on a lightly floured surface. Use a 1 to 1 1/2 inches cookie cutter to cut out small rounds of dough.
Transfer to the prepared pan and bake for 10 minutes at 190C (375F) or until light golden brown. Let cool to room temperature.
You can store the cookies in an airtight container till you're ready to top them and cover them with chocolate.
Otherwise, place a small ball of marzipan (recipe follows) on each cookie, and smooth the marzipan ball down to cover the edges of the cookie. The cookie will look like it has a marzipan dome.
Line a cookie sheet with aluminium foil, parchment or silicon mat.
One at a time, gently drop the marzipan-topped cookies into the hot chocolate glaze. Lift out with a fork and let excess chocolate drip back into the bowl. Place on the prepared pan and let set at room temperature until the coating is firm, about 1 to 2 hours.