1. Trim all fat from beef. Cut the fillets into 12 crosswise pieces of equal size, about 1/2-in. Thick. 2. Melt 2 tbsp of butter in a skillet large enough to hold the pieces comfortably without crowding. Add the pieces of filet and cook over moderately high heat about 35-40 sec. The pieces should be nicely browned on one side. Turn the pieces and cook about 30-45 sec. On the other side. 3. Immediately transfer the pieces to a warm serving platter. Add the mushrooms to the skillet and stir. Add the shallots and cook about 15 sec. Stir in the vinegar and capers. 4. Add the sour cream and stir well. Let the sauce come to a simmer. Add any juices that have accumulated around the steak on the serving platter. Remove the skillet from the heat and swril in the remaining butter. 5. Pour the sauce over and around the steak and sprinkle the dill on top.
