Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Cut the cauliflower into small, bite-sized florets and slice the chicken breast into even strips.
Place the cauliflower and chicken on the baking sheet, then toss with olive oil, sea salt, black pepper, and garlic powder until well coated.
Spread the mixture in a single layer and roast for 20 to 25 minutes, or until the chicken is cooked through and the cauliflower edges are caramelized.
While the tray roasts, whisk the tahini, lemon juice, water, and cumin in a small bowl until the sauce is smooth and pourable.
Transfer the roasted chicken and cauliflower to a plate and drizzle the creamy tahini sauce generously over the top.
Garnish with finely chopped fresh parsley and serve immediately.