This is a variation on a classical osso bucco preparation, using beef instead of veal. Inspired by a recipe in Judith Jones' "The Pleasures of Cooking For One." Risotto would be a reasonably traditional accompaniment.
Sprinkle beef with salt on both sides. Heat oil in a small pot with a tight lid until it shimmers. Add beef and brown well on both sides.
Turn beef on its edge and move to sides of pot. Add onion, carrot, leek and garlic. Saute briefly, until onions and leeks start to go limp. Add pepper, wine and broth. Scrape bottom of pot to dissolve any accumulated fond. Lay beef back down on top of vegetables and lay rosemary across the beef. Cover tightly and transfer to oven. Braise in oven 2 hours.
Combine grated lemon zest, minced parsley and minced garlic.
Serve beef topped with gremolata. Vegetables may be served alongside or discarded, as you like.