Preheat the oven to 220C/200 Fan/Gas 7

Cut 4 pieces of baking parchment to fit 4 shallow baking trays then set aside.

Stir together in a large bowl the flour and the salt.

Stir the olive oil into the water.

Tip all of the liquid into the flour and stir to bring together, eventually using your hands to form a dough.

Working with a quarter of the dough at a time (cover the rest with the upturned bowl to prevent it drying out), put one piece of baking parchment on the worksurface and dust with a little flour.

Place the dough quarter on the parchment, dust a rolling pin and roll the dough out to the approximate shape of the parchment,1-2 mm thick. Cut off any excess if you want the edges to be neat.

For Plain Crackers

Prick the dough all over with a fork to stop it rising too much.

For Seedy Crackers

Brush the dough with a little water, prick it all over with a fork, then sprinkle over the seeds. Take your rolling pin & lightly roll it over the seeds so that they stick to the dough.

Using a knife or pizza wheel, mark out the dough into squares or rectangles:  you don't need to cut all the way through the dough.

Carefully lift the parchment paper onto the baking tray & put it in the preheated oven. Cook until crisp and golden (10-15 min).

Meanwhile: take the second quarter of dough and make another tray of crackers in the same way.

Check after the first 5 minutes: crackers at the edge of the tray may cook very quickly.

If you haven't rolled the dough thinly enough, you may need to turn the crackers over and bake for a further 2-3 minutes to ensure they're crisp all the way through.

Transfer the crackers to a wire rack until cool enough to handle. Break into individual crackers along the marks you cut.

Repeat the process until all 4 trays of crackers are baked.

Leave until completely cold before storing in an airtight container. Crackers will keep fresh for at least 2 weeks.