Yield:

1 13-by-17-inch focaccia

Our onion-and-leek focaccia is an eye-catching flatbread that tastes as good as it looks. Caramelized onions are mixed into the dough, and leeks, rosemary, and chives are artfully arranged on the top. It’s made with a basic yeasted dough. Using bread flour helps give this Italian bread its distinctive chewy texture. It bakes up chewy on the outside and irresistibly soft and pillowy within. Focaccia isn’t difficult to make, but it does take time; the dough needs several rests to allow it to develop. Be sure to let everyone admire the look of this gorgeous bread before you into squares for serving—and watch it go fast.

onion leek focaccia bread martha bakes — Mike Krautter

Ingredients

4 ¾ cups unbleached bread flour, plus more for dusting
2 ¼ cups warm water (about 110 degrees)
¾ teaspoon active dry yeast (not rapid-rise; from one ¼-ounce envelope)
⅓ cup plus 3 tablespoons extra-virgin olive oil, plus more if needed
6 medium onions, halved and sliced ½ inch thick
1 tablespoon plus 1 ½ teaspoons kosher salt
3 leeks, white and light green parts only, roots untrimmed
1 bunch fresh chives
1 bunch fresh rosemary, small sprigs only
Flaky sea salt, for sprinkling

Directions

Place flour in bowl of mixer; mix water and yeast:

Add flour to the bowl of an electric mixer fitted with the dough hook attachment. In a liquid-measuring cup, stir together water and yeast until yeast is dissolved.
Mix yeast mixture with flour; cover and let stand:

Add yeast mixture to flour and mix on medium speed until combined. Cover with plastic wrap and let stand in a warm place until doubled in bulk and bubbling, about 2 hours.
Caramelize onions:

In a large skillet, heat 2 tablespoons oil over medium-low. Add onions and slowly cook until dark golden and caramelized, about 45 minutes. Let cool.
Mix onions into dough:

Add salt and onions to dough and mix on low speed 5 minutes. Increase speed to medium and mix 30 seconds (dough should be loose and sticky).
Fold dough:

Using a dough scraper, turn dough out onto a well-floured surface. Fold bottom edge of dough up toward center of dough and pat gently to deflate. Fold top edge down toward center, overlapping bottom edge slightly and pat gently. Repeat folding process 8 to 9 times, tapping off excess flour as you work (dough will be difficult to handle, but try not to incorporate too much flour).
Place dough in bowl and leave to rise:

Gently transfer dough to a large bowl, seam-side down. Cover with plastic wrap and let stand in a warm place until doubled in volume, about 1 hour.
Repeat folding:

Turn dough out again onto a well-floured surface; repeat folding process. Return dough to bowl, cover with plastic wrap, and let stand in a warm place until doubled in volume, 1 hour more.
Place pizza stone in oven and preheat oven:

Place a pizza stone on floor of a gas oven with racks removed or bottom rack of an electric oven. Preheat oven to 450°F at least 45 minutes (425 degrees if using a convection oven).
Prep leeks and herbs:

Slice leeks lengthwise 1/4 inch thick. Rinse well and pat dry. Coat leeks, rosemary, and chives with 1 tablespoon oil.
Prep baking sheet and spread dough in pan:

Use remaining 1/3 cup oil to coat surface of a 13-by-17-inch rimmed baking sheet. Turn dough out onto sheet, coating bottom with oil. Using oiled fingertips, push dough out toward edges of sheet. If dough starts to retract, let stand 5 minutes, then continue until it reaches edges of sheet.
Add leeks and herbs, cover and let stand:

Arrange leeks, chives, and rosemary lengthwise on dough, pressing gently to adhere. Cover with plastic wrap and let stand 45 minutes, occasionally pressing dough toward edges.
Add salt and more oil if needed:

Liberally sprinkle dough with flaky salt. Dough should be well oiled; if necessary, drizzle with up to 2 tablespoons more oil.
Bake:

Bake, rotating halfway through, until bottom is golden brown, 30 to 35 minutes. Immediately slide focaccia out of pan onto a wire rack. Drizzle with any reserved oil in pan and sprinkle with more flaky salt. Let cool slightly. Foccacia may be served warm or at room temperature.