For the dough, sieve both flours into a large bowl. Mix in the yeast, sugar, zaatar and salt. In a separate bowl mix the warm water and oil together before adding to the dry ingredients. Mix until you have a soft, sticky dough then cover with a cloth and set aside to prove for 10 minutes.
Turn out the dough onto floured surface, and knead the dough for 10 minutes until you have a soft, shiny dough (add a little flour if needed).
Transfer the dough to an oiled bowl and turn it round so that its entire surface has a thin coat of oil. Cover with cling film and set aside to prove for up to an hour.
Flour your hands and knock back the dough by turning it over three to four times in its bowl. Transfer to a floured surface and divide the dough into six equal pieces and form each piece into a ball. Roll each ball out to form a circle approximately 18cm/7in wide and 3mm/â…›in thick (they do not need to be perfect circles). Place each circle on a lightly floured cloth.
Spray the dough circles lightly with water and sprinkle zaatar and sumac over the surface. Leave to prove again for 30 minutes.
Preheat the oven to maximum temperature; it needs to be very hot. Place an upturned roasting tray on the middle to lower shelf (the more uneven the surface the better, so use an old beaten up tray if you have one). Leave the tray to heat up for 20 minutes before baking the flatbreads.
Bake two or three flatbreads at a time for five minutes, or until the flatbreads are puffy and brown spots start to develop. Keep the oven door closed to avoid cooling the oven and keep checking the flatbreads while they cook - they can burn easily. Remove the flatbreads from the oven and place on a cooling rack. Cook the remaining dough circles.