In large bowl, combine 1/3 can soup, ground beef, egg, bread crumbs, pepper and marjoram leaves; mix well. Shape into 6 oval patties.
Heat a large non-stick skillet over medium-high heat. Cook beef patties approximately 8 minutes, turning once. Internal temperature should reach 160F. Remove patties from skillet; keep warm. Remove fat from skillet.
Add remaining soup to skillet, add flour whisking until smooth. Add mushrooms, Worcestershire sauce and water; bring to boiling, stirring to loosen browned bits. Reduce heat to medium, cooking approximately 5 minutes or until mushrooms are tender, stirring occasionally.
Serve beef patties with gravy.