Bring a small pot of water to a boil, gently lower the egg in, and simmer for 6 minutes and 30 seconds for a perfect jammy yolk.
Immediately transfer the egg to an ice bath for 3 minutes, then peel and set aside.
In a medium pot, heat the sesame oil over medium-high heat and sear the pork slices until golden brown, about 2 minutes per side.
Remove pork and add grated ginger, minced garlic, and sliced mushrooms to the pot, sautéing until fragrant and the mushrooms soften.
Pour in the chicken broth and tamari, bringing the liquid to a gentle simmer.
Stir in the miso paste until fully dissolved, then add the ramen noodles and halved bok choy, cooking for 3-4 minutes until the noodles are tender.
Ladle the broth, noodles, and vegetables into a large bowl and top with the seared pork slices.
Slice the jammy egg in half and place on top, garnishing with sliced green onions and black sesame seeds.