Preheat the oven to 425°F. Grease a large sheet-pan with some cooking spray
Chop the chicken into cubes and add it to the sheet pan with the cauliflower florets, sliced bell peppers, and red onion
In a bowl, whisk together the olive oil, parsley, paprika, cumin, salt, black pepper, garlic powder, and harissa until well combined.
Pour the marinade over the chicken and vegetables. Toss well so everything is evenly coated. Spread into a single layer.
Bake for 35-40 minutes, or until the chicken is fully cooked through to 165°F and the veggies have browned. You can set the pan under the broiler at the end for 2 minutes.
In a small bowl, whisk together the tahini, lemon juice, amba, salt, garlic powder, and water until smooth and pourable. Add more water if needed.
Serve the chicken and veggies over rice or warm pita with the amba tahini and fresh parsley