1. Preheat the oven to 375. 2. Peel the potatoes and cut them into slices about 0.125-in. thick. As the potatoes are sliced, drop them into a bowl of cold water to prevent them discoloring. 3. Spread about 1 tsp of the butter over the bottom of a large heavy skillet with a overproof handle. Drain the potato slices and pat dry. Layer them in the skillet, spinkling the layers with small pieces of butter(using all but 2 tablespoon). 4. Cover the skillet closely and cook on top of the stove over moderate heat about 20 min. Uncover and tranfer to oven. Bake 20 min. 5. Meanwhile, sprinkle the steaks with the brandy. Set aside. 6. Heat the remaining butter in a saucepan, add the mushrooms and thyme and cook until wilted. Add the broth and cook until reduced by 0.33333333333333. Add thge sour cream and olives. Remove from heat and set aside. 7. Drain the brandy from the steaks and reserve. Heat the oil in a heavy skillet and add the steaks. Cook over high heat about 3-4 min. on each side (or longer if you prefer your steaks medium to medium-well). Remove and keep hot. 8. Add the brandy to the skillet and cook, stirring to dissolve the brown particles that cling to the pan. Stir in the sour cream sauce and heat through without boiling. 9. Turn the potato cake onto a warmed serving dish. Arrange the steaks on top and spoon a little sauce over them. Serve the remaining sauce separately. This dish: Tournedos a la russe