In a small bowl, combine the flax seeds with 6 tbsp. of espresso coffee and set aside for more or less 10 minutes.
In another bowl, combine the rice flour, the coconut flour, the arrowroot starch, the baking powder, the baking soda, the salt and the cocoa powder.
In a bigger bowl, cream the butter and the sugar. Then gradually add in the flour mix, the melted chocolate, the vanilla, the rice milk, the chocolate chips and the walnuts.
On a cookie sheet, make your cookies (you might have to make two sheets) and place it in the oven.
Cook them for approx. 15 minutes.
Remove them from the oven and place them on a wire rack for 10 minutes to cool down.