Set the oven to 180°C (160°C Fan) and line a baking tray with baking paper.
Mix the flax seeds with the water then set aside for 10 minutes to allow the mixture to go gloopy.
Once the flax seed mixture has gone gloopy, beat it together with the coconut oil and vanilla extract in a stand mixer for 2 minutes until thick.
Add the caster sugar and rapadura and continue beating for 2 more minutes.
Add the nut pulp, brown rice flour, salt, baking powder and chocolate chips and beat on a medium speed until just mixed through (about 30 seconds).
Spoon dollops of the mixture (about 1 tablespoon for each dollop) onto the lined baking tray.
Put the tray into the oven and bake for 15 minutes @ 180°C (160°C Fan).
Then turn the temperature down to 160°C (140°C Fan) and bake for 20 minutes more, until browned.
Remove from the oven and put onto a wire rack to cool.
Notes
If you do not have leftover nut pulp, you could substitute with hazelnut flour or the more widely available almond flour. See the blog post to get tips for making hazelnut flour.
Check the cookies 10 minutes before the full cooking time to see if they are deep golden brown and, if they are, take them out early.