To make the stock, pour water into a large pot and add beef stock; add the beef bones as well, if using. Bring to a boil and skim off foaming scum from surface (this should take about 6-8 minutes). Reduce heat to medium-low, partly cover, and simmer for 2 hours, skimming often. Add onion, carrots, ginger, salt, cinnamon stick, cloves, peppercorns, coriander seeds, and whole star anise and simmer another 1 ½ hours, then remove from heat. 2. Drain stock through a fine sieve, then set aside. Discard bones, carrots, onion, and spices. Once cooled, skim fat from stock. 3. While stock is cooking, soak rice noodles in warm water until soft, about 20 minutes. Drain noodles and set aside. Slice steak into paper thin slices and set aside as well. 4. Once stock is ready, pour in soy sauce and bring liquid to a boil, then reduce heat to very low. 5. Pour boiling stock into 6 serving bowls, add drained noodles, then top equally with bean sprouts, raw onion, scallions, and raw steak slices. Season with cilantro, mint, chili, and lime.