Season lamb shanks generously on all sides with salt and pepper.
Heat the oil over medium-high heat in a large Dutch oven (you want your shanks to be able to fit in one layer). Carefully place the lamb shanks in the oil and sear until brown on all sides. Transfer to a plate.
Add the onions, carrots, celery, and bell peppers to hot Dutch oven and cook until onion is becoming translucent. Add tomato paste and spices (paprika, red pepper flakes, thyme, rosemary). Continue to cook about one minute.
Add tomatoes with their juices, wine, and molasses. Bring to simmer and return the shanks to the pan. Add about one cup of the beef broth, or enough to cover the lamb shanks about half to three quarters of the way. Cover and move to preheated oven.
Cook for one hour, remove from oven and check the level of the liquid. If necessary add more beef broth. Return to oven, covered, and continue to cook for another hour.
(Optional) Skim off any fat/oil that has come to the surface of the pan. Add more salt and pepper to taste.
Serve lamb shanks with sauce and vegetables with couscous, rice, or quinoa, garnished with fresh parsley.