Mix the ground flaxseeds and water and form a "Flax Egg" .
Add in and beat together to form a dough.
Refrigerate the dough for 1 hour.
Place the Brownie base into a four sided tray ( 23cm x 23cm ).
Cook for 15 mins at 165°C.
Roll out the cookie top the same size as the tray and place on top of the partially cooked brownie base.
Continue cooking for 12 - 15 mins or until cooked through