Bring a small pot of water to a boil, carefully lower the egg into the water, and cook for 6.5 minutes for a jammy yolk. Immediately transfer to an ice bath, then peel and halve.
Season the pork tenderloin with a pinch of salt. Heat avocado oil in a skillet over medium-high heat and sear the pork until cooked through, about 4-5 minutes per side. Remove from heat and let rest before slicing into thin medallions.
In a medium pot, sauté the minced garlic, grated ginger, and sliced shiitake mushrooms for 2 minutes until fragrant.
Pour in the chicken bone broth and tamari, bringing the liquid to a gentle simmer.
Whisk the miso paste with a small amount of warm broth in a separate bowl until smooth, then stir it back into the main pot.
Add the brown rice ramen noodles and baby bok choy to the broth. Simmer for 3-4 minutes until the noodles are tender and the greens are bright.
Pour the broth, noodles, and vegetables into a large bowl. Top with the sliced pork, the halved soft-boiled egg, and sliced green onions.