Preheat the oven to 350F and line a baking sheet with baking paper.
Mix all the ingredients in a large mixing bowl. Then add water and stir well.
Set aside and allow to thicken for about 15 minutes. The mixture will thicken and become gooey/gel-like in consistency.
Transfer the mixture over to a baking sheet covered with parchment paper. Spread into a thin layer. You might need to use two baking trays. I like my crackers to be around 4-5mm in thickness.
Bake in the oven for 30 minutes at 175ºC/350ºF. You can adjust the baking time (+/- 10 minutes) depending on how browned/golden and crispy you prefer your seeds to be. They should be golden and crispy at the edges. Keep an eye, though - because of how thin the crackers are, they can burn quickly.
To get evenly cut flax seed crackers, you can cut them halfway through baking. Otherwise, they might be too hard to cut/break evenly. You can use a pizza cutter to do this really quickly, or a knife.
However, you can also simply break the crackers apart after baking, into 'uneven' pieces, for a more rustic look.
Remove the crackers from the oven and leave them to cool completely before transferring to a container/ eating.