In a bowl of a stand mixer fitted with a dough hook combine 1/2 cup of the water and yeast. Stir to dissolve and let it sit for 5 minutes.
In another bowl combine the remaining water with 6 tbsp of the olive oil and whisk together.
Combine the flour and salt in another bowl.
Add the water/oil mixture to the yeast and whisk together.
Add half of the flour and mix on low with the dough hook.
Add the remaining flour and mix on low speed for 5 minutes then increase the speed to medium for another 10 minutes.
Gently knead the dough into a ball shape.
Wipe the inside of a large bowl with a splash of olive oil and set the dough ball into the bowl.
Cover with a towel and let rise for about one hour (first rise)
Punch the dough down to release the air and then knead it into another ball shape placing it back into the bowl for another hour to hour and a half. (second rise)
Repeat the process knocking out the air and forming back into a ball.
Place the dough ball back into the bowl and cover tightly.
Place the bowl with the covered dough into the fridge and let it sit overnight.
Next day bring the dough to room temperature for about 30 minutes.
Line an 18x13x1 inch deep baking sheet pan with parchment paper and set aside.
Shape the dough into a rectangle the same size as the baking pan (18x13)
Place the dough onto the prepared pan stretching it to the edges if needed.
Cover and let rise for about one hour or until the dough has risen slightly to the level of the pan.
Preheat the oven to 450 degrees F.
Brush the surface of the dough generously with the remaining olive oil.
Using your fingers, gently make the dimples by pressing your fingertips into the dough a few times.
Sprinkle the chopped rosemary over the surface followed by the flaky sea salt.
Place the pan into the oven and bake for about 20-23 minutes and the surface is a deep golden color.