Place onions at the bottom of a roasting pan. Lay ribs over the onions (not more than two layers of ribs).

Mix together gochujang, pomegranate juice, soy sauce, crushed tomatoes, lemon zest, ginger and garlic. Spread mixture over ribs.

Transfer ribs, with marinade, to a roasting pan. Cover tightly and bake at 300 degrees Fahrenheit for two to three hours; until easily pierced with a fork.