Heat the oil in a large stock pot or dutch oven over medium high heat. Brown the beef  for 8-10 minutes, flipping as needed to brown all sides evenly. Depending on the size of your pot, you may need to do this in two or more batches. Do not overcrowd the pan, this will cause the meat to steam rather than brown. Transfer the beef to a plate.

You should have about 2 tablespoons of oil/drippings left in the pot, remove anything more than that and discard. Add the ginger, garlic, onion, and scallions and stir them around until they they are fragrant and start to brown about 4-5 minutes. Add the brown sugar and tomato, let cook for an additional minute. Add the star anise, cloves, Sichuan pepper corns, fennel, beef stock, water, soy sauce, and beef. Allow the soup to come to a boil. Reduce the heat to a simmer and let cook for 30 minutes. You'll want to skim the top for gunk. After 30 minutes, cover the pot and allow to cook for an addition 1 ½ - 2 hours. You'll want to keep skimming about every 30 minutes or so.

Remove the beef to a bowl. You can dice the beef into smaller pieces or leave them as is, totally your call. Strain the soup using a fine mesh strainer into another pot or a large serving bowl.

SERVE: Place about 2 ounces of cooked noodles in each bowl along with a few pieces of beef, baby bok choy, scallions, and cilantro. Drizzle with hot chili oil if desired.