Preheat oven to 300˚F. Line two sheet pans (18x13-inches) with parchment paper. Spray three sheets with cooking spray and rub with a paper towel to evenly coat the paper with oil. Line two sheet pans with parchment paper and set the prepared pans and the other sheet of parchment aside.
Stir well again and transfer half of the seed mixture to each of the prepared pans. Flatten mixture with a spatula then place the oiled parchment paper on top of the seed mixture. Using a flat bottomed glass or the bottom of a measuring cup, flatten out the seeds to cover about 3/4 of the pan. Don’t try to spread too thin or the crackers will be too fragile.
Sprinkle lightly with flaky sea salt and place the two pans in the oven. Reduce temperature to 275˚F and bake for 30 minutes. Rotate and swap the position of the pans. Bake for another 30 minutes.
See Café Tips above for more detailed instructions and tips for making this recipe.