Servings: 12

500 grams (3⅔ cups) bread flour 500 grams (3⅔ cups) bread flour
5 teaspoons instant yeast 5 teaspoons instant yeast
1 teaspoon white sugar 1 teaspoon white sugar
2 cups water (470g), cool room temperature (68-70°F) 2 cups water (470g), cool room temperature (68 to 70°F)
8 tablespoons extra-virgin olive oil, divided 8 tablespoons extra-virgin olive oil, divided
1 ¾ teaspoons table salt, divided (2 tsp if Diamond Crystal kosher; 1 tsp if Morton's kosher) 1 ¾ teaspoons table salt, divided (2 tsp if Diamond Crystal kosher; 1 tsp if Morton's kosher)
1 cup cherry tomatoes, halved 1 cup cherry tomatoes, halved
1 cup Castelvetrano olives, pitted and halved (see note) 1 cup Castelvetrano olives, pitted and halved (see note)
1 teaspoon dried oregano 1 teaspoon dried oregano
3/4 teaspoon ground black pepper ¾ teaspoon ground black pepper
½ cup shredded Parmigiano Reggiano ½ cup shredded Parmigiano Reggiano

In a stand mixer with the dough hook, mix the flour, yeast and sugar on medium until combined, about 30 seconds.
With the mixer on low, drizzle in the water, then increase to medium and mix until the ingredients form a very wet, smooth dough, about 5 minutes.
Turn off the mixer, cover the bowl and let stand for 10 minutes. Meanwhile, coat the bottom and sides of a large bowl with 2 tablespoons of oil; set aside.
Sprinkle 1 teaspoon of salt over the dough, then knead on medium until smooth and elastic, about 5 minutes; the dough will be wet enough to cling to the sides of the bowl.
Using a silicone spatula, scrape the dough into the oiled bowl. Dip your fingers into the oil pooled at the sides of the bowl and dribble the oil from your fingertips all over the top of the dough until the surface is covered with dots of oil (this prevents surface drying during proofing).
Cover with plastic wrap (advisable to oil the underside of the plastic wrap in case your bowl isn't quite large enough and the dough rises a bit above the bowl, then the wrap won't stick to it when it falls, which it will), and let stand at room temperature for 5½ to 6 hours. During this time, the dough will double in volume, deflate, then rise again (but will not double in volume again).
After the dough has risen for about 4½ hours, heat the oven to 500°F with a baking steel or stone on the middle rack.
Mist a 9-by-13-inch metal baking pan with cooking spray (or brush well with olive oil just before pouring dough), then pour the remaining 2 tablespoons oil in the center of the pan; set aside.
When the dough is ready, gently pour it into the prepared pan, scraping the sides of the bowl with a silicone spatula to loosen; try to retain as much air in the dough as possible.
The dough will eventually settle into an even layer in the pan; do not spread the dough with a spatula, as this will cause it to deflate.
Set aside while you prepare the tomatoes.
In a medium bowl, use a potato masher to lightly crush the tomatoes (to release their seeds and membranes). Scatter the olives (most curved side up, some cut side up) over the dough, then do the same with the tomatoes, leaving the juice and seeds in the bowl. The skin side of the tomatoes blister nicely when oiled so it's best to put most (but not all) of them skin side up. The olives are aesthetically pleasing with rounded side up, so I put most of them that way, with some pit side up. Try to arrange randomly, neat rows look too symmetrical when baked, rustic is nice for this delightful treat!
If the dough has not fully filled the corners of the pan, use your hands to lightly press the tomatoes to push the dough into the corners. Let stand uncovered at room temperature for 20 minutes.
Drizzle the dough with the remaining 4 tablespoons oil, making sure each tomato gets some. Sprinkle evenly with the oregano, remaining salt, the pepper, and parmesan cheese.
Place the pan on the baking steel or stone and bake until golden brown and the sides of the focaccia have pulled away from the pan, 20 to 22 minutes. Cool in the pan on a wire rack for 5 minutes.
Using a wide metal spatula, slide the focaccia from the pan onto the rack. Cool for at least 30 minutes before serving.

TIP : Don't disturb the dough during its rise. And when transferring the dough to the baking pan, handle it gently. The goal is to retain as much gas in the dough as possible so the focaccia bakes up with an airy texture.  TIP : Don't disturb the dough during its rise. And when transferring the dough to the baking pan, handle it gently. The goal is to retain as much gas in the dough as possible so the focaccia bakes up with an airy texture.
Don't use a baking dish made of glass or ceramic; neither will produce a crisp, browned exterior, and glass is not safe to use in a 500°F oven.  Don't use a baking dish made of glass or ceramic; neither will produce a crisp, browned exterior, and glass is not safe to use in a 500°F oven.
This recipe recreates a light, open-crumbed focaccia from a particular focaccia shop in Bari, Italy. To achieve that texture, the dough must be wet—so wet, in fact, it verges on a thick, yet pourable batter. Resist the temptation to add more flour than is called for. Shaping such a sticky, high-hydration dough by hand is impossible. Instead, the dough is gently poured and scraped into the oiled baking pan; gravity settles it into an even layer. If you have trouble finding Castelvetrano olives, substitute any large, meaty green olive.  This recipe recreates a light, open-crumbed focaccia from a particular focaccia shop in Bari, Italy. To achieve that texture, the dough must be wet-so wet, in fact, it verges on a thick, yet pourable batter. Resist the temptation to add more flour than is called for. Shaping such a sticky, high-hydration dough by hand is impossible. Instead, the dough is gently poured and scraped into the oiled baking pan; gravity settles it into an even layer. If you have trouble finding Castelvetrano olives, substitute any large, meaty green olive.
To slice the baked focaccia for serving, use a serrated knife and a sawing motion to cut through the crust and crumb without compressing it. If desired, serve with extra-virgin olive oil for dipping.  To slice the baked focaccia for serving, use a serrated knife and a sawing motion to cut through the crust and crumb without compressing it. If desired, serve with extra-virgin olive oil for dipping.
For convenience, the dough can be prepared and transferred to the baking pan a day in advance. After it has settled in the pan, cover tightly with plastic wrap and refrigerate. The next day, prepare the toppings. Uncover, top the dough with the olives and tomatoes and let stand at room temperature for 45 minutes, then finish and bake as directed.  For convenience, the dough can be prepared and transferred to the baking pan a day in advance. After it has settled in the pan, cover tightly with plastic wrap and refrigerate. The next day, prepare the toppings. Uncover, top the dough with the olives and tomatoes and let stand at room temperature for 45 minutes, then finish and bake as directed.
Comments section of the original recipe on Milk Street says this freezes well. Cool completely, wrap tightly before freezing. Thaw at room temperature and refresh in a 325°F oven for 5 minutes (that's what Milk Street Team said; another commenter said 300°F for 15 minutes... and might not be a bad idea to lightly oil the original pan it was baked in and reheat the focaccia in it).  Comments section of the original recipe on Milk Street says this freezes well. Cool completely, wrap tightly before freezing. Thaw at room temperature and refresh in a 325°F oven for 5 minutes (that's what Milk Street Team said; another commenter said 300°F for 15 minutes... and might not be a bad idea to lightly oil the original pan it was baked in and reheat the focaccia in it).