sea salt,i like Maldon sea salt flakes - season with salt separately so you can control the amount
Add the flours, baking powder, baking soda, salt and sugar to a mixing bowl and give it a whisk to blend.
Add the olive oil and buttermilk all at once and blend with a paddle attachment (preferred) or wooden spoon until the dough comes to together. Turn out onto a lightly floured surface and knead the dough a few times until it is smooth and well combined.
Flatten into a disc and wrap tightly with plastic wrap. Chill at least three hours or overnight.
Preheat the oven to 375 degrees and line two baking sheets with parchment paper.
After the dough is chilled, divide it into six equal pieces. Working with one piece of dough at a time (keeping the rest refrigerated) roll out the dough on a very well-floured surface until paper thin (about 18 x 10) and oval/rectangle - ish shaped, at least 1/16 inch, turning the dough as you roll to prevent sticking.
Use a sharp knife or pizza cutter and cut the dough into crackers (they don't need to be perfectly even). I usually get about 24 - 2 inch crackers per sheet.
Divide the crackers between the prepared sheets and brush with olive oil using a pastry brush. Combine the seeds for the topping, sprinkle generously and season with salt.
Prick each cracker 2-3 times with a fork and bake for 8 mins or until golden brown, rotating the pans midway through baking.
Cool on a wire rack and repeat with remaining dough.