First make the onions. Put the butter,oil, onions, salt and habanero ( if using) in a large saute pan on a medium heat. Cook, stirring often, for 18 minutes until soft and golden.
Reduce the heat to low and cook for another 4 minutes, stirring often, until they are a deep golden brown. Discard the habanero and stir in the chilli powder.
For the polenta add the milk, stock or water , garlic, curry powder and salt to the same saute pan and place on a medium heat. Once steaming turn the heat right down and slowly pour in the polenta.
Whisk continuously fpr about 7 minutes or untilthe mixture has thickened and is completely smooth. Remove from the heat and stir in the cheese, butter and miso until well combined.
Serve the polenta immediately. Stir the onions through the surface and drizzle with olive oil.