How to Make It
Preheat a charcoal or gas grill to medium- high (450°F to 500°F). Drizzle sourdough bread with 2 tablespoons oil. Place bread and bell peppers on oiled grates, and grill, uncovered, turning often, until bread is toasted, 2 to 3 minutes, and peppers are blackened on all sides, 18 to 20 minutes. Transfer bell peppers to a medium bowl, and cover tightly with plastic wrap; let stand 10 minutes. Cut peppers in half, and peel peppers, reserving any juices in bowl. Discard skin, stems, and seeds. Set peeled peppers and toasted sourdough aside.
Cut squash and zucchini into 1/2-inch-thick slices. Cut onion into 1-inch-thick wedges, leaving root end intact. Cut baby bell peppers in half. Toss vegetables with 3 tablespoons olive oil in a large bowl. Grill vegetables until slightly charred and just tender (see Note for cook times). Remove vegetables from grill, and place in an even layer in a 13- x 9-inch baking dish; sprinkle with 2 teaspoons kosher salt. Whisk together 1 cup oil, 2 tablespoons lemon juice, 1/2 tablespoon Aleppo pepper, and 3 garlic cloves in a medium bowl; pour over vegetable mixture. Cover and let stand at room temperature at least 30 minutes or up to 3 hours.
Reduce gas grill temperature to low (250°F to 300°F), or let charcoal burn down to low. Place sangak on grill grates (if using lavash, brush both sides lightly with olive oil). Grill flatbread, covered, flipping and rotating often, until lightly toasted, 6 to 10 minutes. Set aside.
Tear sourdough bread into small pieces; place in a food processor. Add bell peppers and juices, 1/3 cup oil, 3/4 cup almonds, 6 tablespoons water, 11/2 tablespoons pomegranate molasses, remaining 1/4 cup lemon juice, remaining 1 tablespoon Aleppo, remaining 2 teaspoons kosher salt, and remaining 3 garlic cloves; process until mostly smooth, about 45 seconds. Let mixture stand 10 minutes. If needed, add remaining 3 tablespoons water, 1 tablespoon at a time, pulsing to incorporate, until a thick but spreadable consistency is reached. Season with kosher salt to taste. Roughly chop remaining 1/2 cup almonds; set aside.
Spread muhammara on flatbread. Arrange marinated vegetable mixture on flatbread. Drizzle with 3 tablespoons marinade from dish and remaining 1 tablespoon pomegranate molasses. Sprinkle with chopped almonds. Season to taste with flaky sea salt. Sprinkle with herbs. Drizzle with remaining 3 tablespoons olive oil just before serving.
Grill baby bell peppers over direct heat, uncovered, 4 minutes. Grill squash and zucchini over direct heat, uncovered, 6 to 8 minutes. Grill red onion over direct heat, uncovered, 10 minutes, then another 10 minutes over indirect heat.