In the Oven : Cheesy Focaccia with Caramelized Onions and Sautéed Spinach

Taking a break from the desserts this week to bake a savory Focaccia. Posting date is February 3rd.

Cheesy Focaccia with Caramelized Onions and Sautéed Spinach

Yield: One extra-large focaccia (about 12 servings)

For the Focaccia Dough
2 1/2 cups all-purpose flour, plus more as needed
2 1/4 cup bread flour
2 3/4 teaspoon instant dry yeast
2 3/4 teaspoon salt
2 cups lukewarm water (100 to 110 degrees F)
1/3 cup good-quality olive oil, plus more for oiling
Cornmeal for dusting

For the Topping
1/4 cup good-quality olive oil, divided, plus more for brushing
1 medium red onion, thinly sliced
3 1/2 cups loosely packed baby spinach
2 tablespoons chopped fresh rosemary
2 tablespoons chopped fresh thyme
Salt, to taste
Freshly ground black pepper, to taste
Dried oregano, to taste
2 cups shredded whole-milk mozzarella or other cheese of your choosing
1/2 cup freshly grated Pecorino Romano or other hard cheese of your
choosing, plus more for sprinkling
Red pepper flakes, to taste

Make the Focaccia Dough

Place the flours, yeast, and salt in the bowl of a standing mixer fitted with the paddle attachment and beat on low speed until combined. Add thewater and 1/3 cup of the olive oil and mix on low speed until the dough just begins to come together. Turn off the mixer, switch to the dough hook attachment, and mix on medium speed until the dough is smooth and starts to release from the sides of the bowl (it is okay if the dough still sticks to the bottom of the mixing bowl). If the dough feels too wet and is not releasing, add additional all-purpose flour, 2 tablespoons at a time, until the dough releases.

Dust a work surface with a sprinkling of flour and stretch the dough into a long rectangle (about 9 inches by 20 inches). Fold each side of the dough onto itself creating a letterfold. Tuck the dough into a makeshift ball and place in a lightly oiled bowl. Cover with plastic wrap and set aside in a warm-ish place (at least 72 degrees F) for 20 to 30 minutes. Remove the dough and repeat this process (stretching the dough into a rectangle, letterfolding, tucking into a ball shape, and placing in covered bowl). Wait another 30 minutes and repeat this process a third time.

Lightly spray a 13-by-18-inch light-colored metal half-sheet pan or two 9-by13-inch glass or light-colored metal baking pans with nonstick cooking spray and line with parchment paper. Use your fingers to smear a little olive oil (no more than a tablespoon) evenly across the parchment and sprinkle with an even dusting of cornmeal.

Transfer the dough to the prepared pan(s) and stretch into a rectangle inside the pan (do not attempt to stretch the dough into corners of the pan just yet). Cover with plastic wrap and let the dough rest (still at room temperature) for about 20 minutes. Uncover and stretch the dough into the corners of the pan. (If the dough feels resistant to stretching into the pan corners at this time, cover with plastic wrap and wait 10 more minutes.)

Preheat the oven to 450 degrees F and position the rack in the center. Place a baking pan filled with water on the rack below where you will be baking the focaccia. The steam from the pan will give the crust a nice crunchy exterior while keeping the interior moist and chewy.

Make the Topping
In a medium skillet or sauté pan, heat 1 tablespoon of olive oil over medium-low heat. Add the onion and sauté for 20 to 25 minutes, or until the onion is soft and translucent. Remove the onion from the pan and set aside. Add the spinach to the sauté pan, cover, and cook until the spinach is cooked through, about 5 minutes. Turn off the heat and set aside until cool. Squeeze the spinach dry and set it aside

Poke the dough. If your finger leaves an indentation, it is ready; if it doesn’t leave an indentation, wait an additional 5 minutes and test again. Toss the rosemary with the remaining 3 tablespoons of olive oil. Brush the rosemary oil all over the top of the dough. Sprinkle with thyme, salt, pepper, and oregano.

Place the focaccia in the oven, one rack above the pan filled with (now boiling) water, and bake the focaccia for 10 minutes, rotating the pan halfway through the baking time, or until dough starts to brown on top. Once the dough has browned, remove the pan from the oven and, leaving a small border of crust, top the dough with the onion, spinach, cheeses, and red pepper flakes. Place the focaccia back in the oven and bake until the cheese is bubbly and browned.

Remove from the oven, sprinkle with more Pecorino Romano and salt to taste, and brush the edges with a little bit more olive oil. Serve immediately.

Focaccia tastes best directly from the oven, though leftover focaccia can be stored in the refrigerator, tightly covered, for up to 2 days. Reheat in a 275 degrees F oven for about 10 minutes or until warm to the touch before serving.

Excerpted from Baked Elements: Our 10 Favorite Ingredients by Matt Lewis and Renato Poliafito. Copyright © 2012 by Matt Lewis and Renato Poliafito. Excerpted by permission of Stewart, Tabori & Chang, an imprint of Abrams. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.