For the chutney, heat the olive oil in a large frying pan over a low heat and gently fry the ginger, chilli, lime zest, lime juice and garlic until softened, but not coloured.
Add the cinnamon, coriander, sugar, vinegar and mango. Increase the heat and bring to the boil.
Reduce the heat and simmer for at least 40 minutes, until reduced to a sticky jam consistency.
Meanwhile, for the blackening mixture, place all of the blackening ingredients into a bowl and mix well.
For the halibut, season the fish steaks with salt and freshly ground black pepper.
Press each side of the fish into the blackening mixture and shake off any excess.
Dry fry the coated steaks in a hot frying pan for 2-3 minutes on each side, or until just cooked through.
To serve, place the cooked halibut steaks onto plates and garnish with the lime wedges, fresh coriander and serve with rice.