Guest recipe by Anya von Bremzen
Author of The New Spanish Table
2 tablespoons olive oil, plus more for brushing the coca
1 medium-size white onion, quartered and thinly sliced
4 cups thinly sliced drained roasted peppers in oil (from four 14- to 16-ounce jars)
5 tablespoons granulated sugar
2 tablespoons sherry vinegar, preferably aged, or best-quality red wine vinegar
Coarse salt (kosher or sea)
All-purpose flour, for dusting the rolling pin
1 pound store-bought pizza dough, thawed if frozen
Confectioners' sugar, for dusting the coca
1. Heat the 2 tablespoons olive oil in a large skillet over medium-low heat. Add the onion and cook until limp but not browned, 5 to 7 minutes, stirring occasionally. Add the roasted peppers and cook for about 5 minutes, stirring. Add the granulated sugar, vinegar, and 2 tablespoons water and stir until the sugar dissolves. Cover the skillet, reduce the heat to low, and cook until the liquid is reduced, about 10 minutes, stirring from time to time. Season with salt to taste and let the pepper mixture cool completely.
2. Place an oven rack in the center of the oven and preheat the oven to 450°F. Lightly brush a 17- by 11-inch baking sheet with olive oil.
3. Lightly flour a work surface. Using a floured rolling pin, roll out the dough so it is roughly as large as the baking sheet. Transfer it to the oiled baking sheet and brush it with olive oil. Spread the filling evenly on top.
4. Bake the coca on the center rack until it is light golden and baked through, 18 to 20 minutes. Let the coca cool to warm (or make the coca ahead, which actually adds to its flavor; reheat it gently before serving). Cut the coca into rectangles (I use sturdy kitchen scissors for this), dust it very lightly with confectioners' sugar, and serve at once. Makes 1 large coca; serves 12 as a tapa.