Preheat the oven to 200 °C (fan). Line a snug ovenproof dish or baking tray with baking paper.
Make the spiced yoghurt marinade: Whisk together Greek yoghurt, olive oil, garlic, cumin, coriander, turmeric, paprika, chilli flakes, salt and pepper until smooth.
Prepare the cauliflower: Remove any tough outer leaves but leave the tender inner ones. Trim the base so it sits flat. Place in the prepared dish.
Coat the cauliflower: Spoon the yoghurt mixture over the cauliflower, using your hands or a brush to coat it evenly all over, including underneath.
Roast covered: Loosely tent a large sheet of foil over the top (making sure it doesn’t touch the surface). Pinch around the edges to seal. Roast for 35–40 minutes until the centre starts to soften.
Uncover and brown: Remove the foil and roast for another 25–30 minutes, or until the cauliflower is deep golden and tender when pierced with a skewer.
Make the tahini yoghurt: Whisk together yoghurt, tahini, lemon juice and water until smooth. Season with salt and adjust to a pourable consistency.
Toast the almonds: During the final few minutes of roasting, scatter the flaked almonds on a small tray and toast in the oven until golden.
Serve: Drizzle the tahini yoghurt over the cauliflower, then top with pomegranate, toasted almonds and parsley. Serve warm with lemon wedges.