Prepare the chia seed gel by combining the ground chia seeds and water in a small bowl. Let it sit for 5-10 minutes until it forms a gel-like consistency.
In a large mixing bowl, whisk together 240g of the cassava flour, chickpea flour, salt, baking powder, and bicarbonate of soda until evenly combined.
Create a well in the centre of the dry ingredients mixture.
Pour the melted butter, milk, chia seed gel, egg whites, and honey into the well. Mix the ingredients together using a silicone spoon initially, then switch to using your hands, ensuring all ingredients are well incorporated.
Once the dough has more or less come together then tip out onto a clean work surface and knead the mixture for 1-2 minutes until a smooth ball of dough forms.
Heat a non-stick pan (or cast iron skillet) over medium heat.
Divide the dough into 6 equal-sized balls (120-130g each).
Lightly Flour the work surface and a rolling pin with some of the remaining cassava flour.
Roll each dough ball into an 18cm (7 inch) round using a rolling pin, rotating and adding more flour as needed to prevent sticking. Also run your finger around the edges as you go, neatening them up as they have a tendency to go a little shaggy.
Cook each flatbread in the pre-heated pan on a medium heat for 2-2½ minutes on each side, or until golden brown.
As each flatbread is cooked, remove it from the pan and immediately cover loosely with a tea towel to keep it warm and prevent drying out.