01 -
Stir yeast into bread flour in a bowl. Add salt, followed by 4 teaspoons oil, and water. Stir with a spoon until a wet, sticky dough forms.
02 -
Cover bowl and let dough sit at room temperature for 12 to 14 hours.
03 -
Uncover dough and transfer to an oiled work surface. Using oiled hands, press and push the dough into a rectangle, 16x12 inches in size.
04 -
Fold dough into thirds horizontally, then fold vertically into thirds. Transfer smooth side up into a generously oiled pan.
05 -
Cover the pan with plastic wrap and let rest until almost doubled in size, about 1 hour.
06 -
Using oiled hands, fold once more into thirds horizontally, then into thirds vertically to develop gluten structure.
07 -
Flip dough, smooth side up, on the pan. Cover with plastic wrap and let rest for 1 hour more.
08 -
Unwrap and stretch and fold dough once more in each direction using oiled hands.
09 -
Transfer, smooth-side up, into a generously oiled metal baking pan. Lightly drizzle with additional olive oil and stretch to fit the pan. Cover and let rest for 2 hours.
10 -
Preheat the oven to 425°F (220°C).
11 -
Unwrap and poke holes in the top of the dough using oiled fingers to create the traditional focaccia texture. Scatter rosemary and flaky sea salt evenly over the surface.
12 -
Bake in the center of the preheated oven until golden brown, about 30 minutes.
13 -
Let cool in the pan for 10 minutes, then transfer to a wire rack and let cool to room temperature, about 30 minutes before slicing.