1/2 package active dry yeast
1-1/2 cups unbleached all-purpose flour
1/2 cup warm tap water
1/2 teaspoon salt
1 cup dried thyme
1 cup sumac
1 tablespoon sesame seeds
3 tablespoons olive oil
Whisk together the yeast, 1 tablespoon of the flour and 1/4 cup warm water in a small bowl and let stand until mixture develops a creamy foam; about 10 minutes. If mixture does not foam, discard and start over with new yeast.
Next, stir together the salt and 3/4 cups flour in a large bowl. Then add yeast mixture and remaining 1/4 cup of warm water. Stir until smooth, then mix in another 1/2 cup flour. If dough sticks to your fingers, stir in just enough flour to make the dough start to pull away from the side of the bowl. This dough may be wetter than familiar Italian pizza dough.
Knead the dough on a lightly floured surface with floured hands. Lightly re-flour the work surface and your hands when dough becomes too sticky. Work the dough until it is smooth, soft and elastic; about 10 minutes. Form dough into a ball, then generously dust with flour and put in a medium bowl. Cover the bowl with plastic wrap and let dough rise in a warm, draft-free place until it doubles in size; about 1 to 1-1/4 hours.
While dough is rising, combine thyme leaves, sumac and sesame seeds in a medium mixing bowl. Sumac is a dark red berry that grows on bushes throughout the Middle East and some parts of Italy. Sumac is sold ground or in dried seed form and can be found at most Middle Eastern markets, or can be ordered from an online specialty company. Next add the olive oil to the mixture to form a paste. This paste is the zaatar mixture.
When the dough has fully risen, place it onto a floured surface, and press down to form into a disk shape. Spread with the zaatar mixture and place on a pizza stone or oiled pizza pan. Cook in a 350-degree oven for 3 to 4 minutes, or until the dough is crispy and brown. Serve warm.