Focaccia With Olives & Onions

Ingredients for the sponge:
2 1/2 teaspoons (1 package) active dry yeast
2/3 cup warm water, 105-115 degrees F
1 cup unbleached all-purpose flour

Ingredients for the dough:
1/2 cup water, room temperature
1/3 cup dry white wine (or additional water)
1/3 cup light extra virgin olive oil
2 1/2 cups unbleached flour, plus 1 to 3 T as needed
1 3/4 teaspoons kosher salt
2 teaspoons yellow cornmeal

Ingredients for the topping:
2 T olive oil (divided use)
1 cup thinly sliced yellow onion
1/2 cup black olives, pitted
2 T fresh oregano leaves, chopped
1/2 cup sun-dried tomatoes, drained and finely chopped
1/2 teaspoon coarse sea salt

To prepare the sponge:
Sprinkle the yeast over the warm water in a large mixing bowl, whisk it in and let stand about 10 minutes, until creamy. Stir in the flour and beat until smooth. Cover tightly with plastic wrap and let rise until puffy and bubbling, about 30 minutes.

To make the dough:
Add water, wine and olive oil to sponge. If making the dough by hand, whisk in 1 cup flour and the salt, then beat in the rest of the flour until you have a dough that is very soft and sticky. Knead on a floured surface 6 to 8 minutes, until the dough is smooth. Use a dough scraper or long, narrow spatula to lift the dough occasionally and sprinkle the surface with 1 to 2 additional tablespoons flour.

If making dough with a mixer, add water, wine and olive oil to sponge. Using paddle attachment, add 21/2 cups flour and the salt and mix until dough comes together. Change to dough hook and knead 3 minutes on medium speed, stopping once or twice to scrape sides of bowl. Add a little extra flour if needed. After dough is mixed, place in a lightly oiled container, cover with plastic wrap and let rise until doubled, about 1 hour.

While dough is rising, heat 1 tablespoon olive oil in a saute pan over medium heat. Add onions and saute until golden, about 10 minutes. Remove from heat and stir in olives, oregano and sun-dried tomatoes; set aside to cool.

Sprinkle cornmeal into a 10 1/2-by-15 1/2-inch pan. Press dough into pan, dimple it with your fingertips and spread onion mixture over top. Cover with a clean kitchen towel and let rise 45 minutes, until puffy and doubled. About 30 minutes before baking, heat oven to 400 degrees. Just before baking, sprinkle remaining tablespoon olive oil and the salt over topping.

Place pan on bottom oven rack and bake 25 minutes, until golden. Spray oven walls and floor with water from a spritzer bottle three times during first 10 minutes of baking. (If topping begins to brown too much, cover loosely with aluminum foil.) Immediately remove focaccia from pan with a wide spatula and cool on a rack. Serve warm or at room temperature.

Makes a 10 1/2-by-15 1/2-inch focaccia