Stir the yeast mixture and add the salt, 1/4 cup of olive oil, and 3 cups of the flour. Stir together with a wooden spoon and transfer to a well-floured flat surface. Knead, pushing the dough using the palms of your hands, for approximately 5 minutes, until the dough looks smooth and stretchy, adding more flour as needed if the dough becomes too sticky. The goal is to have a dough that is stretchy, soft and smooth.
Preheat the oven to 400 F and brush a 9x13” baking pan or dish with 2 tablespoons of olive oil.
Stretch the dough out with your hands to fit the baking pan, stretch using your hands to fit the pan, cover again with the dish towel and let it rise again until doubled, about 30 minutes.
Using your finger tips, poke multiple holes into the surface of the dough. Drizzle the top of the dough with the remaining 2 tablespoons of olive oil, sprinkle with the flaked sea salt and rosemary and bake for approximately 20 minutes, until golden brown. Cool slightly (brush with a bit of extra olive oil if desired at this point) and remove from the pan. Cut into pieces and serve!