Preheat oven to 325°F
Combine tamari, miso, honey, vinegar, garlic, ginger and red pepper flakes in a small bowl and whisk well to combine
Pour marinade over beef and toss to coat evenly
Add meat to roasting dish, cover and roast for 3 hours
Remove from oven and check for doneness; if meat pulls apart easily, shred into large chunks and toss in juices; if not, return covered to oven for 30 more minutes
Once meat has been shredded, increase oven temperature to 450°F and return to oven uncovered for 15 minutes until the top layer of meat is crispy
Garnish with sesame seeds and green onion
