01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - Remove tough outer leaves from cauliflower and trim stem so the head sits flat on the baking sheet.
03 - In a small bowl, whisk together olive oil, cumin, smoked paprika, turmeric, coriander, garlic powder, salt, and black pepper.
04 - Place cauliflower on prepared baking sheet. Brush generously with spiced oil mixture, ensuring marinade covers entire surface and reaches into crevices.
05 - Roast for 55-65 minutes until deeply golden, tender when pierced with a knife, and slightly crisp on edges.
06 - While cauliflower roasts, whisk tahini, lemon juice, minced garlic, and salt in a bowl. Gradually whisk in cold water, 1 tbsp at a time, until smooth and pourable.
07 - Transfer roasted cauliflower to serving platter. Drizzle generously with tahini sauce. Top with chopped parsley, toasted sesame seeds, and lemon wedges. Slice into wedges to serve.