To cook beef rouladen, first lay out eight pieces of round steak, that are about 1/4 inch thick, and spread mustard onto one side of each piece. Place a small wedge of onion, a slice of dill pickle and one strip of bacon over the mustard.
Roll each piece of steak so that it enfolds the mustard, pickle, onion and bacon, and then secure it with a wooden toothpick. Next, heat some vegetable oil in a large pan and brown the pieces of round steak. Once the steak has been cooked, pour out any excess juices that have collected in the bottom of the pan.
Pour three cups of beef broth into the pan along with the meat and bring the broth to a boil. Cover the pan, reduce the heat, and allow the broth and steak to cook together for 1 1/2 hours. Next, remove the meat and add 1/3 cup of flour and 1/2 cup of water to the broth. Stir the mixture until the broth has thickened. Stir in 1/4 cup of sour cream once the broth, flour and water have been combined. Remove the wooden toothpicks from the pieces of steak and place them back into the broth. Serve immediately.