Bring the stock to a very light simmer in a large pot, then add the beef base, fish sauce, hoisin, scallion halves, ginger, cloves, star anise, cinnamon stick and 1 tablespoon of the soy sauce. Simmer for 30 minutes.
Using a spider or strainer, remove all the solids, leaving you with just the broth. Taste and adjust the seasoning with the additional tablespoon of soy sauce if it needs more salt, or hoisin if it needs more sweetness. Bring the broth back to a light simmer.
Meanwhile, set up your bowls. On the bottom, divvy up the rice noodles, then top with the shaved beef. Pour in some simmering broth. Garnish with the bean sprouts, cilantro, mint, scallions sliced on the bias, jalapenos and lime wedges. Drizzle with extra hoisin if desired.