Preheat oven to 325°F. Heat avocado oil in a large dutch oven or braiser over medium high heat. Season meat generously with salt and pepper then sear each side until golden brown, about 3 minutes per side. Remove meat and set aside.
Add mirin to dutch oven and scrape the bottom of the pot to release anything that has stuck. Add in miso, honey, bone broth and tamari and whisk well.
Add ginger, garlic, green onions and chili flakes to your broth and stir to combine. Return meat to your pot, bring sauce to a simmer then cover and braise in the oven until meat is tender and falling off of the bone, about 2 ½ -3 hours.
Remove meat from dutch oven and strain off aromatics. Return broth to dutch oven then skim off and discard as much of the fat from the top of the broth as possible.
Bring broth to a simmer over medium heat and continue simmering until sauce has reduced enough to coat the back of a spoon, about 3-5 minutes.
Return meat to sauce and toss well to coat evenly.
