Preheat the oven to 180°C (350°F).
Prepare the dough: In a large bowl, combine the flour, sugar, salt, and olive oil. Add the warm water and knead the mixture with your hands, pressing until the ingredients come together to form a soft, pliable dough. Divide the dough into three equal portions and shape each into a ball.
Make the zaatar filling: In a bowl, mix the sunflower oil, zaatar, sumac, and sea salt until you obtain a thick paste.
Roll out the dough: Lightly flour your rolling pin and roll each dough ball out as thinly as possible on a lightly floured piece of parchment paper.
Cut and fill the crackers: Using a pizza cutter, score the dough into 5 cm (2-inch) squares. Gently spread the zaatar filling over the surface with the back of a spoon, leaving a small border around the edges.
Bake: Transfer the parchment paper, along with the scored dough, directly onto a baking sheet. Bake for 15–20 minutes, or until the crackers are golden brown and crispy. Keep a close eye on them, as some crackers may brown faster than others. That’s perfectly fine! Simply remove the browned crackers from the oven and return the remaining ones to bake until they reach the desired color and crispness.
Repeat: Continue with the remaining dough. You can bake one batch while rolling out the next to save time.
Happy baking, and enjoy your homemade zaatar and sumac crackers!