Preheat the oven to 350 F / 175 C.
Combine all dry ingredients (except water) in a big bowl.
Add water and stir to combine. The dough will be sticky and a little wet. That’s ok, just let it sit for 5 - 10 minutes on the countertop, chia and flax seeds will absorb that extra moisture. Don't let it sit for too long or the dough will get super hard and you are not going to be able to roll it out.
Place the dough on a large sheet of parchment paper, then lay another sheet of parchment paper on top (IMPORTANT: use a strong, high-quality parchment paper or it will stick to the dough and break. I’ve been there!). Use a rolling pin to evenly roll out the dough into a thin layer, about 1/10 of an inch thick (2 – 3 mm).
Remove the top sheet of parchment paper and transfer the dough, the bottom sheet of parchment paper included, to a baking tray.
Bake for 30 - 40 minutes, or until dry and slightly golden. Remove from the oven and cool down.
Break the large cracker into smaller pieces and enjoy!
Store them in an air-tight container for up to 1 week.