Preheat your oven to 400°F. While it heats, slice the cabbage into 1-inch thick wedges and place on one baking sheet. On a separate sheet, drain and rinse the chickpeas. Toss the cabbage with 3 tablespoons of olive oil, 1/4 teaspoon of salt, and 1/8 teaspoon of black pepper, then spread in a single layer. In a bowl, combine the chickpeas with 4 tablespoons of olive oil, the remaining 1/4 teaspoon of salt, and 3 teaspoons of harissa, mixing well to coat evenly. Spread the chickpeas on their sheet in a single layer. Place both sheets in the oven—the cabbage will roast for 18-22 minutes until the edges are caramelized and tender, while the chickpeas roast for 22-25 minutes until crispy and golden.
While the vegetables roast, thinly slice the red onion into 1/8-inch half-moons and mince the garlic cloves, placing both in a large bowl. In a small saucepan over medium heat, warm the remaining 4 tablespoons of olive oil and add the sesame seeds, toasting for 1-2 minutes until fragrant and lightly golden. Add the coriander and red pepper flakes, cooking for another 2-3 minutes to bloom the spices and release their oils. I like to lower the heat to medium-low before adding the vinegar and honey—this prevents the vinegar from evaporating too quickly and allows the honey to dissolve smoothly into the warm dressing. Once combined, immediately pour the hot dressing over the onions and garlic in the bowl and let it sit, which will soften the onions while they absorb the flavors.
When the roasted cabbage and chickpeas are done, transfer them to a large serving bowl and toss together while still warm. Pour the warm dressing with the marinated onions and garlic over the roasted vegetables and toss everything together until well coated. The warmth of the vegetables will help them absorb the dressing flavors beautifully. Finish by folding in the fresh cilantro just before serving to keep it bright and vibrant.
While the salad comes together, toast the thick-cut bread slices in a toaster or under the broiler until golden and crispy. Spread a generous layer of labneh on each slice—I find that the creamy richness of labneh balances beautifully with the warm, spiced vegetables and adds a cool, tangy element. Serve the roasted cabbage salad alongside the labneh toast or spoon it directly on top of the bread for a more composed presentation.