Serves: Makes one 12 by 17-inch focaccia
- 1 cup warm (105¼ to 115°F) water
- 1 teaspoon active dry yeast
- 1 cup unbleached all-purpose flour
- ½ cup lukewarm water
- ⅓ cup dry white wine
- ⅓ cup extra virgin olive oil
- 1 tablespoon kosher or sea salt
- 2 tablespoons cornmeal
- 2¾ cups unbleached all-purpose flour
- 4 tablespoons plus 2 teaspoons extra virgin olive oil
- 2 tablespoons extra virgin olive oil
- 1 tablespoon minced fresh Italian parsley
- 1 small clove garlic, finely minced
- Large pinch of kosher or sea salt
- Large pinch of hot red pepper flakes (optional)
- 3 medium leeks, rinsed well and halved lengthwise, then sliced crosswise⅓ inch thick (white and pale green parts only)
- 1 tablespoon minced fresh thyme
- Kosher or sea salt
- 16 cherry tomatoes, or more if small, halved
To make the sponge, put the warm water in a small bowl and sprinkle the surface with the yeast. Let stand for 2 minutes to soften, then whisk with a fork to blend. Let stand until bubbly, about 10 minutes. Add the flour and stir with a wooden spoon until smooth. Cover with plastic wrap and leave at room temperature for 24 hours.
To make the dough, put the sponge in the bowl of a stand mixer fitted with the paddle. Add the lukewarm water, wine, olive oil, salt, and cornmeal. Mix on low speed to blend. With the mixer running, add the flour gradually. When the flour has been incorporated, raise the speed to medium and knead with the paddle for 5 minutes. The dough will be moist and a little sticky, but it will eventually clear the sides of the bowl.
Scrape down the sides of the bowl and the paddle. Cover the bowl with plastic wrap and let the dough rise at room temperature until doubled, about 1½ hours.
Using the 2 teaspoons olive oil, generously grease a 12 by 17-inch rimmed baking sheet. Punch down the dough and turn it out onto the prepared pan. With well-oiled fingers, poke and prod the dough into a rectangle that fills the pan. The dough is elastic and will want to spring back. If it resists your attempts to flatten it enough to cover the pan, let it rest for 5 minutes and try again. If it still springs back from the edges, let it rest 5 to 10 minutes longer and try once more. You should be able to flatten it sufficiently after a couple of rests. Let rise, uncovered, at room temperature until puffy, about 1½ hours.
About 45 minutes before you are ready to bake, position a rack in the center of the oven, then line the rack with baking tiles or a baking stone. Turn on the oven to 425°F and let it preheat for at least 45 minutes.
To make the seasoned oil, in a small bowl, whisk together the olive oil, parsley, and garlic. Add the salt and hot pepper flakes and set aside for at least 30 minutes to develop flavor.
Heat 2 tablespoons of the olive oil in a medium skillet over moderate heat. Add the leeks and thyme, season with salt, and stir well. Cover, reduce the heat to moderately low, and cook until the leeks are soft but not mushy, 12 to 15 minutes, uncovering to stir occasionally. Let cool.
Sprinkle the leeks evenly over the surface of the risen dough. Then nestle the cherry tomato halves, cut side up, evenly over the surface, pushing them down into the dough with your fingers. Brush the surface with the remaining 2 tablespoons olive oil and sprinkle with salt. Place the baking sheet directly on the tiles or baking stone and bake until the focaccia is golden brown, 20 to 25 minutes.
Loosen the focaccia with an offset spatula, then slide it out of the baking sheet and onto a rack. Brush while hot with the seasoned oil, then let cool for about 20 minutes before cutting. Serve warm.