1)On a baking tray lined with aluminium foil place the chopped onions and carrots and beef shanks and drizzle the oil on top and toss the around in the tray to coat.
2)Cook the beef shanks along with the vegetables in the oven for about an hour and be sure to flip the beef shank after 1/2 hour of cooking to ensure that it is evenly cooked.
3)Start a large pot of boiling water as the beef shanks are cooking.
4)To the pot of water now add the oven cooked shanks bones and all along with the veggies and bring to a boil.
5)Season the broth with five spice powder and mix well. Gradually add the fish sauce next and mix and let it boil for some time.
6)Cut the beef into paper thin slices and set aside.
7)In a large noodle bowl add the vermicelli noodles, cilantro, sprouts, onions and beef slices and pour over the broth.
8)Serve hot and eat immediately with some sriracha sauce on top or your favorite sauce. Best enjoyed on a cold winters day.