Preheat the oven to 425°F (220°C). Line a baking sheet with parchment paper.
Cut the cauliflower into small florets and place them into a large mixing bowl.
In a separate small bowl, whisk together the olive oil, cumin, paprika, turmeric, garlic powder, coriander, cayenne, salt, and black pepper. Pour this mixture over the cauliflower and toss until all florets are well coated.
Spread the cauliflower evenly on the prepared baking sheet. Roast in the preheated oven for 25-30 minutes, stirring halfway through, until golden and tender.
While the cauliflower is roasting, cook the quinoa or couscous according to package instructions using water or vegetable broth. Set aside.
In a small bowl, mix the tahini, lemon juice, minced garlic, and water. Whisk until smooth, then season with salt to taste. Adjust the consistency by adding more water if needed.
Once the cauliflower is done, assemble the bowls by placing a scoop of quinoa or couscous at the bottom.
Top with roasted cauliflower, diced cucumber, cherry tomatoes, red onion, and chopped parsley.
Drizzle the tahini sauce over the top before serving.
Enjoy your delicious Cauliflower Shawarma Bowls!