2 lb. flank steak
1/2 c. lemon juice
2 tbsp. butter, softened
1 tsp. prepared mustard

Put flank steak in Pyrex baking dish and pour lemon juice over it. Cover and refrigerate several hours, turning occasionally to soak up lemon juice. Stir butter and mustard together. Place steak on a broiling pan. Discard remaining lemon juice. Spread half of butter mixture over top. Broil 10 minutes; turn and spread other side with remaining butter mixture. Broil for 8 minutes more. Remove from oven and slice on diagonal. Serves 4 to 6.