Heat 3/4 c water in a tea kettle, in the microwave or in a very clean coffee pot. The water should be very, very hot, but not boiling. Combine hot water with 1 1/2 c cool water to make lukewarm water. It should read between 100-110F on a food thermometer.
Make sure to check the date of your yeast, to ensure its fresh. Combine dry active yeast and water in a large mixing bowl. Whisk together to combine and let sit. Water should look cloudy with several bubbles foming during and immediately after whisking. Sit for 5 minutes.
Stir in flour and salt using a spatula. Work flour into a shaggy dough ensuring no flour srtreaks remain. Pour 1/4 c olive oil into a well oiled bowl. Rub some of the oil around the sides. Transfer dough to the large, well oiled bowl. Flip the bottom part of the dough to the top, ensuring all parts of the dough are coated with some oil. Cover with plastic wrap or a well fitted lid. Leave to sit at room temperature for 4 hours. Dough should double in size.
Preheat oven (170F or preheat feature on oven) for 15 minutes. Turn off. Using two forks, gather 1/6 of the circumference of bowl of dough pulling edges in towards the middle. You're gathering a small portion of the edge of the dough and pulling it up and over into the center of the bowl. Repeat all the way around the bowl until the dough has formed into a smaller"ball." Using 1-2 tbsp olive oil, grease a non stick 11X13 cake pan or 15X18 "jelly roll" baking sheet. Pour gathered dough onto the well greased pan. If any oil remains, pour on top of the dough. Place uncovered pan of dough into a preheated oven thats been turned off for 90-120 minutes.
Once dough has risen to double in size, pull from the oven and test to see if its ready. You'll know its ready when you press a small indentation and the dough slowly rises. Once ready, heat the oven to 440F (preheat at least 15-20 minutes).
Oil your hands and press fully press fingers into the dough, creating lots of dimples. Pour 2-3 tbsp remaining olive oil over the dough. Scatter za'atar seasoning over the dough. Top with flaky salt. Bake in the fully preheated oven for 18-22 minutes or until the top is golden brown.
Remove from oven and cool in the pan for 5 minutes. Slice and enjoy!