Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
In a large mixing bowl, combine the cauliflower florets, cubed chicken breast, and sliced red onion.
Drizzle with olive oil and sprinkle with turmeric, garlic powder, sea salt, and black pepper, tossing until everything is evenly coated in the golden spices.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the pieces aren't crowded so they roast rather than steam.
Roast for 20-25 minutes, tossing halfway through, until the chicken is cooked through and the cauliflower edges are beautifully caramelized.
While the tray roasts, whisk together the Greek yogurt, lemon juice, and lemon zest in a small bowl until smooth and creamy.
Plate the roasted chicken and vegetables, drizzle generously with the zesty yogurt sauce, and garnish with fresh parsley before serving.