Begin by placing the seeds and oats in a bowl, add the water, oil, honey and sea salt. Give it a good stir. Set to one side for 20 minutes.
Add the cornflour and stir well. Have two baking trays ready, lined with parchment paper. Mine measure 40 x 30 cm.
Preheat the oven 190Cfan.
Divide the mixture in half and spread evenly on the two trays, making sure there are no gaps. Place in the oven and bake for 15 minutes.
Remove the trays from the oven to cut. Flip the now hard yet pliable dough onto a large board and cut into even sized rectangles or squares. Reduce the oven temperature to 175Cfan. Place the crispbreads back onto the tray and pop back into the oven to crisp up. This can take between 25-35 minutes. Check every 10 minutes. The crispbreads in the centre of the tray tend to take longer than the ones at the edges. Have a look at the underside, they should be lightly golden and completely dried out.
Once done leave to cool. Store in an airtight container for up to 2 weeks.
To ensure the crispbread is completely crisp, once they're done, turn the oven off and leave the door open for 5 minutes to cool down quickly. Then shut it and leave the crispbread there for several hours.