Sprinkle lamb with pepper and salt. Heat an extra-large Dutch oven over medium-high heat. Add half of lamb; cook 3 minutes on each side or until browned. Remove from pan; set aside. Repeat with remaining lamb. Reduce heat to medium; add onion and next 4 ingredients. Cook 5 minutes, scraping pan to loosen browned bits. Add tomatoes, rosemary, and bay leaves. Return lamb to pan. Bring to a boil. Cover, reduce heat, and simmer 2 hours or until lamb is tender; discard bay leaves and liquid.
Cook bacon in a large nonstick skillet over medium-high heat until crisp. Remove bacon from pan, and crumble. Discard pan drippings. Add bacon, soup, and remaining 3 ingredients to pan. Simmer, uncovered, 30 minutes, stirring occasionally.
Serve lamb shanks on a bed of lentil ragoût.
NOTE: The discarded remaining braising liquid can be used to make a delicious soup; just skim the fat first.