Whisk the miso paste, oil, water, ginger, salt and pepper in a large bowl to combine, then toss the cauliflower pieces in the dressing to coat.
Place the cauliflower pieces in a single layer on a baking tray and roast for 15 minutes, then flip each piece over. Roast for a further 10-15 minutes until soft, slightly dark and caramelised.
Serve warm topped with parsley and sesame seeds (if using).
Notes
Make sure you cut the cauliflower into large florets as smaller pieces can cook too quickly or become mushy or burned.The cauliflower should be in a single layer that is even on the baking sheet. This will keep them from steaming and becoming soggy.Depending on your oven, it makes take a few minutes longer or less to finish cooking. Test with a fork through the middle to see if it slides through easily.If your cauliflower hasn't browned enough to your personal tastes. Broil the top for 1-2 minutes.