Preheat your oven to 450°F

Stir together flour, baking powder, salt, and pepper in a medium bowl. Make a well in the centre, and add the water and oil. Stir together with a wooden spoon until a dough forms.

Knead dough gently on a floured work surface 4 or 5 times. Divide dough into about 6 equal pieces and roll out each piece into a rustic long baton shape. The dough should be very thin. Lightly brush top with additional oil and sprinkle with sea salt and a little more pepper if you like. (Roll out dough on parchment and transfer sheet and all to the baking sheet, or just spray baking sheet with cooking spray and bake directly on baking sheet.)

Bake in batches, until flatbread crackers are pale golden and browned in spots, 8 to 10 min. Flatbread crackers can be made 2 days ahead and cooled completely, then kept in an airtight container at room temperature.