Preheat the oven to 400F.
While the oven is preheating, make the cauliflower marinade by whisking together olive oil, salt, garlic powder, paprika, dried parsley, sumac, and black pepper in a bowl.
Once the marinade is ready, prep the cauliflower by removing the bottom leaves and rinsing the cauliflower head. Make sure to dry it off completely and use a knife to cut off any browned bits as well.
Place the cauliflower into a dutch oven so it is upside down (core side up). Then, pour around ⅓ of the marinade onto the bottom of the cauliflower so it seeps into the inside and drips down the core.
Flip the cauliflower over so the head is now on top and use a basting brush to coat the cauliflower with the removing marinade.
Once the cauliflower is coated, cover the dutch oven with it's lid and add to the oven. Roast covered for about 25-30 minutes.
At the 30 minute mark, remove the lid and continue roasting the cauliflower for another 10-20 minutes until it is browned on top and cooked through. If you prefer softer cauliflower, then roast for longer. For a more firm cauliflower with a little bite, roast for less time.
Remove the cooked cauliflower from the oven and set aside.
About 5 minutes before the cauliflower is done roasting, make the maple tahini sauce by adding the tahini, water, lemon juice, maple syrup, garlic powder, and salt to a bowl. Whsik together until smooth.
Carefully remove the whole roasted cauliflower from the dutch oven and place it onto a serving dish. Then, pour the maple tahini sauce on top. As a final touch, top the cauliflower with pomegranate seeds and fresh parsley.
To serve, slice into 6 wedges and enjoy!