1. Preheat your oven. 390°F (200°C)
2. Wash and cut the cauliflower head into florets and put into a bowl.
3. Dice the chestnut mushrooms into quarters and place into the bowl with the cauliflower florets.
4. Coat the cauliflower and mushrooms with a dash of olive oil, nigella seeds, sea salt and black pepper, then shake around until they are covered.
5. Transfer to an oven dish and place into the oven.
6. Cook for 25 minutes until the cauliflower edges have browned and the mushrooms are soft and juicy, and serve hot.

Enjoy.