Preheat the oven to 400 degrees
Slice the bottom of the core off the cauliflower so that it sits evenly on the baking sheet. Drizzle 2 tbsp of the olive oil over the cauliflower and rub it in evenly. Sprinkle with ½ tsp salt. Pour ½ cup of water in the pan and cover with foil. Roast for 20 minutes.
In the meantime, combine the yogurt, olive oil, lemon juice, garlic, smoked paprika, cumin, coriander, turmeric and salt. Set aside.
Make chimichurri- In a food processor, combine the parsley, vinegar, garlic, oregano and crushed red pepper. Process until smooth; season with salt and pepper. Transfer the sauce to a bowl and pour the olive oil over the mixture. Let stand for at least 20 minutes
After 20 minutes, remove the cauliflower from the oven and spread ¾ of the yogurt sauce all over. Roast for another 25 minutes without the foil.
Remove the cauliflower from the oven. It should be tender outside and fork-tender inside. Top the cauliflower with more sauce and sprinkle with the herbs. Serve with chimichurri.