In a large bowl, combine the flour, salt, and yeast and mix well.

Add the room-temperature water and stir with a spoon until no dry flour remains.

Add ⅓ of the olive oil and mix well, kneading lightly with your hands for 1–2 minutes until the dough is infused.

Cover tightly with plastic wrap and let rest at room temperature for 1 hour.

Remove the plastic wrap. With oiled fingertips, fold the dough over itself by lifting, stretching, and folding the edge of the dough toward the opposite side of the bowl.

Turn the bowl and repeat until you’ve made a full circle of folds (about 4–6 folds total).

Cover again and let rest at room temperature for 15–20 minutes.

Repeat the folding process, then cover tightly once more and refrigerate for 18–36 hours.

The dough is ready when it is alive with fermentation and has puffed up to 2–3 times its original size.

Preheat the oven to 500°F at least 1 hour in advance, with the rack in the centre.

Remove the dough from the refrigerator and let it sit at room temperature for 15 minutes.

Dust the top of the dough with flour, then gently scrape and pour the dough onto a lightly floured work surface.

With floured hands, shape the dough by tucking the dough underneath itself, rotating as you go, until it forms a tight ball.

Pour the remaining olive oil into a 10- or 12-inch cast-iron skillet.

Transfer the dough to the pan, seam-side down. Drizzle the top with a touch of olive oil.

Cover tightly with plastic wrap and let rise at room temperature for about 1 ½ hours, or until very soft, puffy, and filling the pan.

Using your fingertips, poke into the dough all the way to the bottom, creating dimples across the surface.

Pour the remaining olive oil over the dough. Sprinkle generously with salt.

Bake for 25–30 minutes, or until golden brown on top.

Remove from the oven. Cool in the pan for 5 minutes, then use a thin spatula to transfer the focaccia to a wire rack.

Cool for at least 10 minutes before slicing.