Preheat oven to 325º. Spread mustard over rouladen. Sauté whichever fillings you like and add the seasonings as you wish.
Place dill pickle slice (or diced) on large end of meat. Place filling on top. Roll up. Secure with toothpicks. Roll in seasoned flour. Brown all sides in oil and butter mixed.
Take out meat. Make gravy from drippings. Pour gravy on meat in casserole dish.