Wipe, remove superfluous fat, and pan broil seven minutes a porterhouse or cross-cut of the rump steak cut one and three-fourths inches thick. Butter a plank and arrange a border of Duchess Potatoes, using three times the recipe, close to edge, using a pastry bag and rose tube. Remove steak to plank, put in a hot oven, and bake until steak is cooked and potatoes are browned. Spread steak with butter, sprinkle with salt, pepper, and finely chopped parsley. Garnish top of steak with sautéd mushroom caps, and put around steak at equal distances halves of small tomatoes sautéd in butter, and on top of each tomato a circular slice of cucumber.