Roasted Chickpea & Cauliflower Pitas with Sun-Dried Tomato Sauce

Preheat oven to 450°F. Place onion in a medium heatproof bowl. Combine vinegar, 1/4 cup water, maple syrup and 1/2 teaspoon salt in a small saucepan; bring to a simmer over medium-high heat, stirring occasionally. Pour over the onion; set aside to pickle for 30 to 60 minutes, stirring occasionally.

Meanwhile, toss cauliflower, chickpeas, oil, cumin, coriander, garlic powder, turmeric and 1/2 teaspoon salt together on a large rimmed baking sheet; spread in an even layer. Roast, stirring once, until the cauliflower is tender and golden brown, about 30 minutes.

Combine yogurt, herbs, sun-dried tomatoes, tahini, lemon juice, harissa and the remaining 1/4 teaspoon salt in a food processor or blender; process until smooth, about 1 minute, scraping down the sides as needed. With the motor running, drizzle in the remaining 3 to 5 tablespoons water until the desired consistency is reached.

Drizzle 1/2 cup of the yogurt mixture over the roasted cauliflower and chickpeas; toss to coat evenly.

To assemble, spread the remaining 1/2 cup yogurt mixture over pitas. Top with lettuce leaves. Spoon the cauliflower mixture over the lettuce (about 1 1/2 cups each). Drain the onions; divide among the pitas. Garnish with additional torn herbs, if desired.