Mix the peanut butter in a bowl with a fork with the ginger, garlic, soy sauce and the juice of half the lime. Stir the tin of coconut milk to break up any solids that have settled at the top. Add 3 tablespoons of the coconut milk from the tin to the peanut butter mixture, saving the rest of the tin for later. Add 40ml of water to the peanut butter mixture and stir to combine. Taste the peanut butter sauce and add more soy/lime or peanut butter according to your preference.
Preheat the oven to 200°C.
Place the cauliflower in a small roasting dish and pour 50ml of water around the base. Spoon the peanut butter sauce over the cauliflower so that the entire surface of the cauliflower is covered and no white spots are visible. Lightly grease a piece of tin foil large enough to cover the cauliflower snugly and secure around the head of cauliflower, greased side down. Place the tray in the oven for 15 minutes.
Remove the tray from the oven, lift away the foil and discard. Pour the rest of the coconut milk around the cauliflower. Drain the chickpeas and add to the tin with the spring onions and the remaining lime half. Stir the chickpeas, coconut milk and spring onions together and return the tray to the oven for 35-40 minutes until a burnished, copper peanut butter crust has formed on the cauliflower and a sharp knife passes through easily.
When the curry has had its time in the oven, sprinkle over the coriander and chilli flakes and slice into wedges to serve.
You can leave out the chickpeas, spring onions and coriander if you’d prefer to serve the cauliflower on the side with a noodle dish or stir fry. Alternatively, add greens such as kale, spinach or finely sliced cabbage to the roasting tin 3 minutes before the end of the cooking time.
If you can’t get hold of fresh ginger, 1 teaspoon of dried, ground ginger will do in its place. Finely sliced red onions will work as well as spring onions and mint can replace the coriander.