The evening before baking, mix the dough (see step 2) and let it spend the night in the refrigerator.

Combine the flour, water, sugar, salt, and yeast in the large bowl of a stand mixer with the dough hook attached. Mix on medium speed for about 5 minutes, stopping to scrape down the sides of the bowl once or twice. Let the dough rest for 5 minutes and then mix on medium low for another 3-4 minutes, until it's relatively smooth. At this point, the dough will resemble melted mozzarella and be very sticky. If you stretch a small piece, it will barely hold together.

Coat a bowl large enough to hold the dough when it doubles in size with 1 tablespoon olive oil. Transfer the dough to the bowl and flip the dough to coat it with the oil. Cover the bowl well with plastic and refrigerate it overnight, or for at least 8 to 10 hours.

Remove the bowl of dough from the refrigerator about 3 hours before you intend to bake it (2 hours on a warm day). The dough should have nearly doubled in size. Drizzle two 9-inch cake pans with olive oil and rub with a paper towel to coat. Line bottom of the pans with parchment paper. (DON'T SKIP THIS STEP OR YOUR BREAD WILL STICK TO THE PAN, EVEN A NON-STICK PAN - I learned this the hard way.) Drizzle a tablespoon of olive oil into each pan and spread it with your fingers to coat the parchment paper.

With a rubber spatula, divide dough in two approximately equal pieces and slide each one into a prepared pan. The dough will sink beneath its own weight, expelling some gas, but retaining enough to keep an airy gluten network that will grow into nice holes.

Drizzle 1 tablespoon of the olive oil on top of each piece of dough. (Don't worry if some rolls off onto the pan; it will all be absorbed eventually.)

Push the dough out to the sides of the pans with your fingers, creating hollows in the dough. At first you might only be able to spread the dough to cover about one-half to three-quarters of the pan. Don't force the dough when it begins to resist you. If this happens just let the dough rest for 10 or 15 minutes. The oil will prevent a crust from forming.

After letting the dough rest you will be able to push the dough to fill or almost fill the entire pan. It should be about ¼ to ½ inch thick. If it doesn't stay in place at the edges, don't worry; the dough will fill the corners as it rises. Drizzle the dough once more with a few teaspoons of olive oil.

Cover the pans loosely with plastic wrap or a clean kitchen towel, and let the dough rise at room temperature until it's about 1-½ times its original size. This will take 30 minutes to an hour or an hour and a half, depending on the temperature of the room. Thirty minutes before baking, heat your oven to 450°F.

Just before baking, remove the plastic wrap and sprinkle dough in pans with a few pinches of sea salt, the rosemary and a few generous grinds of black pepper. Put the pans on the middle shelf of the hot oven and reduce the heat to 425°F. After 15 minutes, rotate the pan to ensure even baking.

Check the dough after another 5 minutes. If it's done, it will be golden brown on top and, if you lift a corner of the dough, the underside will be golden as well. If not, return the pan to the oven for another 1 to 2 minutes and check again.

Use a metal spatula or table knife to release the dough from the sides of the pan. Slide the focaccia onto a cooling rack. Let cool for 20 minutes before cutting and serving.