Remove the membranes from the kidneys, cut into small pieces, put aside. Cook the onions with the butter until tender. Add the diced apple and cook for 10 minutes. Sprinkle with curry powder and flour, stir and raise the heat a little. Add salt, and pepper and cook for 30 minutes. Rub the sauce through the fine mesh of a food mill and reserve. Sear the kidneys in 2 tablespoons butter and 1 tablespoon oil for about 5 minutes. Add the cognac and flame. Remove the kidneys, keep warm. Pour the sauce into the frying pan and reduce over a high heat. Add the kidneys just to reheat them. Serve with wild rice.
