Bring a small pot of water to a boil, carefully lower the egg into the water, and simmer for 6.5 minutes. Immediately transfer to an ice bath, peel when cool, and set aside.
Cook the soba noodles in boiling water according to package directions, then drain and rinse with cold water to prevent sticking.
Slice the pork belly into small cubes and the pork tenderloin into thin medallions. Season both with sea salt and black pepper.
In a small skillet over medium heat, cook the pork belly cubes until the fat has rendered and they are golden and crispy. Remove the belly and set aside, leaving the rendered fat in the pan.
Increase the heat to medium-high and sear the pork tenderloin medallions in the pork fat for 2-3 minutes per side until cooked through. Remove and set aside.
In a medium saucepan, heat the sesame oil over medium heat. Add the minced ginger and garlic, sautéing for 1 minute until fragrant.
Pour the chicken bone broth into the saucepan and bring to a gentle simmer. Add the baby bok choy and cook for 2 minutes until tender-crisp.
Remove the broth from the heat and whisk in the miso paste until completely dissolved and the broth appears creamy.
Place the cooked soba noodles in a deep bowl and pour the hot broth and bok choy over them.
Top the ramen with the seared pork tenderloin, crispy pork belly, the halved soft-boiled egg, and sliced green onions before serving.