Cooking Method for Chicken Korai. Serves 4. To make the Onion Puree, bring a small pan of water to the boil and add some chopped onions. Boil until soft, drain and puree with a hand blender or in a food processor.Freeze any extra you make for next time. Pour the oil into a large saucepan bring up to a high heat.Add the whole seeds and cook until they sizzle and crackle then add the chopped onions and reduce the heat to low.oil until soft, drain and puree with a hand blender or in a food processor. Freeze any extra you make for next time. Pour the oil into a large saucepan bring up to a high heat. Add the whole seeds and cook until they sizzle and crackle then add the chopped onions and reduce the heat to low.