Lightly spread mustard on each slice of steak; sprinkle with salt and pepper. Place 1 bacon strip and a few onion wedges on each slice; roll up and secure with wooden picks. Brown in a skillet in oil; drain. Add broth; bring to a boil. Reduce heat; cover and simmer for 1.5 hours or until meat is tender. Remove heat and keep warm. Combine flour and water until smooth; stir into broth. Bring to a boil, stirring constantly until thickened and bubbly. Remove wooden picks from meat and return to gravy; heat through. Sprinkle with parsley if desired.