Cauliflower Shawarma With Spicy Tahini

Name: Cauliflower Shawarma With Spicy Tahini
Cook time: 45 min
Total time: 45 min
Cuisine: Middle Eastern
Ingredients: 5 tablespoons extra-virgin olive oil, plus more as needed; 1 1/4 teaspoons ground cumin; 1 1/4 teaspoons sweet paprika; 3/4 teaspoon fine sea or table salt, plus more as needed; 1 teaspoon ground coriander; 1/4 teaspoon ground turmeric; 1/4 teaspoon freshly ground black pepper; Pinch of ground cayenne; 1 large head cauliflower (about 2 1/2 pounds), trimmed and cut into bite-size florets; 1 large red onion, cut into 1/4-inch wedges; Pita or flatbread, for serving; 1/4 cup coarsely chopped parsley, plus more for serving; Chopped tomato, cucumber and olives, for serving; 1 tablespoon fresh lemon juice, plus more to taste; 1 to 2 teaspoons harissa paste or other hot sauce, or a large pinch of Urfa or Aleppo pepper, plus more to taste; 1 fat garlic clove, finely grated, passed through a press or minced; 1/4 teaspoon fine sea or table salt; 1/3 cup tahini; 1/3 cup ice water, plus more as needed