Soft-boil the egg in boiling water for 6.5 minutes, then immediately chill in an ice bath before peeling and slicing.
Cook the soba noodles in a separate pot of boiling water until tender, then drain and set aside.
Brown the ground pork in a saucepan over medium-high heat with sea salt and black pepper until no longer pink.
Add the minced garlic, grated ginger, and sliced shiitake mushrooms to the pork, cooking for 2 minutes until aromatic.
Pour in the beef bone broth and tamari, bringing the liquid to a gentle simmer.
Submerge the baby bok choy in the hot broth for 2 minutes until it becomes tender and bright green.
Assemble the bowl by placing noodles at the bottom, ladling the pork and broth over them, and finishing with the egg, green onions, and sesame oil.