Preheat oven to 325F
In a medium bowl, whisk together orange juice, soy sauce, miso paste, ginger paste, honey, rice vinegar, garlic, black pepper, and red chili flakes to make the marinade
Pat dry the chuck roast and place it in a dutch oven
Pour the marinade on top and flip the meat a few times to coat it well
Cover with a lid and place in the oven for 3 ½-4 hours
At the 3 ½ hour mark, pull the meat out and use two forks to shred it apart
If not easily shredding, pop it back in the oven for 30 minutes more
Remove from the oven, shred all the meat and toss with the juices
Optional: place the pot back in the oven under the broiler on high for 3-4 minutes for crispy bits
Remove and serve
