Preheat oven to 450 degrees. Wash the cauliflower and trim any longer leaves. Leave some leaves on the base of the cauliflower as they are delicious when roasted. If the cauliflower does not sit flat, slice the bottom of the cauliflower until it sits evenly.
Heat a large pot of water to boiling. Add the cauliflower, reduce heat, and cover. Simmer for about 8-10 minutes.
Drain the cauliflower on a cooling rack or some paper towels for a few minutes until it cools down.
Prepare a baking sheet with parchment paper. Place the cauliflower on the baking sheet and drizzle with oil. Rub the turmeric, cumin, paprika, and salt until evenly covering the cauliflower. Use gloves to avoid any staining from the turmeric. Drizzle with a little more olive oil and flaky salt if desired.
Roast for 45 minutes until golden and slightly charred. Adjust the time based on how large your cauliflower is.
While the cauliflower roasts, make the tahini sauce. Whisk together the tahini, lemon juice, garlic, and oil until smooth. Add water and whisk well until you reach a drizzling consistency. Add more water if necessary.
Place the roasted cauliflower on a serving dish and let cool for a few minutes. Drizzle with the tahini sauce and top with parsley, cabbage, peanuts or pistachios, and extra flaky salt.
Store any leftovers in a covered container for 3-5 days.