Using a very sharp knife, cut all the corn from the ears and puree all but 1 cup of the corn. Set aside the corn kernels and leave the pureed corn in the processor. Heat half the butter in a large saucepan and add the onion, cooking over a medium heat until the onions have softened, about 5 minutes. Add the garlic and chillies and continue cooking for a further minute then add the onion mixture to the pureed corn in the processor. Process this mixture together with water and cornflour until relatively smooth. Heat the remaining butter in the same saucepan and add the pureed mixture, cooking for five minutes, or until the corn mixture is quite thick. Add the stock and stir while the mixture heats. Simmer over a low heat for 20 minutes or until the soup is quite thick and smooth. Add the cream or milk and half the parsley and coriander and continue to simmer gently, seasoning to taste with salt and freshly ground pepper. Add the reserved corn kernels and stir to distribute. Serve the soup garnished with remaining parsley, coriander and crumbled feta. Per serving: 760 Calories (kcal); 40g Total Fat; (43% calories from fat); 17g Protein; 100g Carbohydrate; 93mg Cholesterol; 427mg Sodium Food Exchanges: 6 Grain(Starch); 0 Lean Meat; 1/2 Vegetable; 0 Fruit; 7 Fat; 0 Other Carbohydrates Converted by MM_Buster v2.0n.