Place flour in shallow dish. Dip pork chops in flour, coating both sides. In heavy, large skillet, melt butter over medium-high heat; add chops and brown on both sides. Remove chops from skillet. Reduce heat to medium. Add onions, garlic, rosemary, salt (if desired), and pepper to skillet. Cover and cook for 5 minutes, stirring twice. Uncover and cook for 5 minutes more or until onions are browned, stirring occasionally.
Add wine; boil gently until wine is reduced by half. Stir in beef broth. Return chops to skillet. Cover and simmer for 8 to 10 minutes more or until chops are slightly pink in centers and juices run clear (instant read thermometer inserted into center of chop registers 160 degrees F). Remove chops to platter; cover and keep warm.
For sauce, gently boil juices and onions for 2 to 4 minutes or until slightly thickened, stirring constantly. Spoon onions and sauce over chops. Makes 4 servings.