Rub the butter over the bottom of a shallow flameproof casserole or skillet. Trim off the bottoms and any damaged outer leaves of the endive and cut the heads into diagonal slices about 1" thick. Put them in the pan with salt and pepper to taste, lemon juice and water. Press a piece of buttered foil on top of the endive and cover with a lid. Cook over low heat for 7-8 minutes or until the endive is tender. Shake the pan occasionally. Sprinkle with the chopped parsley and serve.