Preheat the oven to 180 celsius (350 fahrenheit) and line a baking sheet with baking paper. Place 4 of the bananas on the baking tray and drizzle with the honey. Toss to combine. Grate the nutmeg over the top and roast for 30 minutes or until the tops of the bananas are golden and caramelised. Set aside to cool.
Slice the remaining bananas and line a 22cm (9 inch) x 7.5cm (3 inch) loaf tin with baking paper. Add the coconut oil and brown sugar to the bowl of an electric mixer fitted with a paddle attachment and cream until pale. Add the eggs one at a time and mix well before adding the roasted banana and vanilla.
Switch off the mixer and sift in the flour and baking powder and fold through using a wooden spoon or spatula. Add the banana slices and coconut milk and fold through until just combined.
Pour the mixture into the prepared loaf tin and then trim a piece of baking paper to size and place of the top of the loaf. Bake for 30 minutes at 180 celsius (350fahrenheit) before reducing the temperature to 160 celsius (320 fahrenheit) and baking for a further 30 minutes, or until a cake tester comes out cleanly. Remove from the tin and place on a wire rack to cool.