A spiced onion jam contrasts nicely with earthy mushrooms in our vegetarian take on this Palestinian flatbread.

Mushroom Musakhan
MAKES two 15 by 8-inch flatbreads, serving 4 to 6 VEG
WHY THIS RECIPE WORKS Musakhan is a popular Palestinian dish featuring a flatbread topped with roasted chicken, caramelized onions, pine nuts, and tart sumac. We wanted to create a mushroom version that still had the distinctive flavor of the original dish. Sautéed portobello mushrooms made a perfect topping; tasters loved their robust flavor and juicy flesh. Next we made a warm-spiced caramelized onion jam. The traditional base, taboon bread, is a thick, crisp flatbread that is traditionally cooked in a clay oven. For a version we could make at home, we made a dough with whole-wheat flour and bread flour for good flavor and bite. To ensure crisp edges, we cooked the flatbreads on a preheated baking stone, and we superheated the oven by briefly turning on the broiler before baking the musakhan. Some baking stones can crack under the intense heat of the broiler; be sure to check the manufacturer’s website. Serve with yogurt.

DOUGH
1½ cups (8¼ ounces) whole-wheat flour
1 cup (5½ ounces) bread flour
2 teaspoons honey
¾ teaspoon instant or rapid-rise yeast
1¼ cups ice water
2 tablespoons extra-virgin olive oil
1¾ teaspoons salt

TOPPINGS
½ cup extra-virgin olive oil
2 tablespoons minced fresh oregano or 2 teaspoons dried
4 garlic cloves, minced
1½ tablespoons ground sumac
¼ teaspoon ground allspice
⅛ teaspoon ground cardamom
2 pounds onions, halved and sliced ¼ inch thick
2 teaspoons packed light brown sugar
Salt and pepper
¼ cup pine nuts
2 pounds portobello mushroom caps, gills removed, caps halved and sliced ½ inch thick
2 tablespoons minced fresh chives

1. FOR THE DOUGH Pulse whole-wheat flour, bread flour, honey, and yeast in food processor until combined, about 5 pulses. With processor running, slowly add ice water and process until dough is just combined and no dry flour remains, about 10 seconds. Let dough rest for 10 minutes.
2. Add oil and salt to dough and process until dough forms satiny, sticky ball that clears sides of bowl, 30 to 60 seconds. Transfer dough to lightly oiled counter and knead by hand to form smooth, round ball, about 30 seconds. Place dough seam side down in lightly greased large bowl or container, cover tightly with plastic wrap, and refrigerate for at least 18 hours or up to 2 days.
3. FOR THE TOPPINGS Combine 1 tablespoon oil, oregano, garlic, sumac, allspice, and cardamom in bowl. Heat 2 tablespoons oil in 12-inch nonstick skillet over high heat until shimmering. Add onions, sugar, and ½ teaspoon salt and stir to coat. Cook, stirring occasionally, until onions begin to soften and release some moisture, about 5 minutes. Reduce heat to medium and continue to cook, stirring often, until onions are well caramelized, 35 to 40 minutes. (If onions are sizzling or scorching, reduce heat. If onions are not browning after 15 to 20 minutes, increase heat.) Push onions to sides of skillet. Add oregano-garlic mixture to center and cook, mashing mixture into skillet, until fragrant, about 30 seconds. Stir oregano-garlic mixture into onions.
4. Transfer onion mixture to food processor and pulse to jamlike consistency, about 5 pulses. Transfer to bowl, stir in pine nuts, and season with salt and pepper to taste; let cool completely before using.
5. Wipe skillet clean with paper towels. Heat 2 tablespoons oil in now-empty skillet over medium-high heat until shimmering. Add half of mushrooms and ½ teaspoon salt and cook, stirring occasionally, until evenly browned, 8 to 10 minutes; transfer to separate bowl. Repeat with 2 tablespoons oil, remaining mushrooms, and ½ teaspoon salt; transfer to bowl and let cool completely before using.
6. One hour before baking, adjust oven rack 4 inches from broiler element, set baking stone on rack, and heat oven to 500 degrees. Press down on dough to deflate. Transfer dough to clean counter, divide in half, and cover loosely with greased plastic. Pat 1 piece of dough (keep remaining piece covered) into 4-inch round. Working around circumference of dough, fold edges toward center until ball forms.
7. Flip ball seam side down and, using your cupped hands, drag in small circles on counter until dough feels taut and round and all seams are secured on underside. (If dough sticks to your hands, lightly dust top of dough with flour.) Repeat with remaining piece of dough. Space dough balls 3 inches apart, cover loosely with greased plastic, and let rest for 1 hour.
8. Heat broiler for 10 minutes. Meanwhile, generously coat 1 dough ball with flour and place on well-floured counter. Press and roll into 12 by 8-inch oval. Transfer oval to well-floured pizza peel and stretch into 15 by 8-inch oval. (If dough resists stretching, let it relax for 10 to 20 minutes before trying to stretch it again.) Using fork, poke entire surface of oval 10 to 15 times.
9. Spread half of onion mixture evenly on dough, edge to edge, and arrange half of mushrooms on top. Slide flatbread carefully onto baking stone and return oven to 500 degrees. Bake until bottom crust is evenly browned and edges are crisp, about 10 minutes, rotating flatbread halfway through baking. Transfer flatbread to wire rack and let cool for 5 minutes. Drizzle with 1½ teaspoons oil and sprinkle with 1 tablespoon chives. Slice and serve.
10. Heat broiler for 10 minutes. Repeat with remaining dough and toppings, returning oven to 500 degrees when flatbread is placed on stone.