Make shawarma mix: In a small bowl, whisk 4 tablespoons extra virgin olive oil, 2 tablespoons lemon juice, 3 cloves garlic (grated), 2 teaspoons ground coriander, 3 teaspoons paprika, 1 teaspoon ground cumin, ½ teaspoon cinnamon, 1 teaspoon salt, and black pepper.
Roast the vegetables: Heat the oven to 425°F (220°C). Add 1 large cauliflower cut into florets, 1 can chickpeas (rinsed), and 3 medium red onions (sliced) to a large sheet pan. Drizzle the shawarma mix over the veggies and toss well to coat. Spread everything out in a single layer and roast for 25 to 30 minutes or until golden and lightly charred on the edges.
Make the serving sauce: Whisk ½ cup Greek yogurt or tahini, lemon juice, and salt in a small bowl. Add cold water, a tablespoon at a time, until the sauce becomes creamy and pourable. Set aside.
Assemble the bowls: Add 1 cup cooked quinoa, ¼ cup chopped parsley, and a squeeze of lemon directly to the sheet pan. Toss with the roasted vegetables so the quinoa picks up all the pan flavors. Spoon into bowls and top with diced cucumber and tomato. Drizzle generously with the sauce and enjoy.
