In a small bowl, whisk together the honey, tamari, hoisin sauce, sesame oil, five spice powder, grated ginger, and minced garlic.
Season the pork tenderloin evenly with sea salt and black pepper.
Place the pork in a shallow dish and pour two-thirds of the honey-tamari mixture over it, reserving the remaining sauce for glazing.
Allow the pork to marinate in the refrigerator for at least 30 minutes to absorb the aromatic spices.
Preheat your oven to 400°F and line a baking sheet with parchment paper or a wire rack.
Roast the pork for 20 to 25 minutes, brushing with the reserved glaze halfway through, until the internal temperature reaches 145°F.
While the pork rests for 5 minutes, steam the baby bok choy for 3 to 4 minutes until the leaves are wilted and the stems are crisp-tender.
Slice the pork into thin medallions and serve immediately alongside the steamed greens.