Step 2: Roll out the dough

Picture of Roll out the dough
Divide and set aside about one third of the dough

Roll the remaining two-thirds out on a lightly-floured surface, until it's about 4mm thick - it should be big enough to just fit on a 30cm (12 inch) cookie sheet

Transfer the dough to the cookie sheet (you can do this by rolling it gently around the rolling pin, then unrolling it in place.  If your cookie sheet is not very reliably nonstick, cover it first with a sheet of reusable nonstick baking film or lightly oiled greaseproof paper

Use a chopstick or other straight edge to give the surface a rock-like texture

Press a bottle cap or other small circular object into the surface here and there to mark out some shallow depressions