Begin by placing your chuck roast in a slow cooker or a large oven-safe pot. Pat the meat dry with paper towels to help seasonings adhere better, and set it aside while you prepare the marinade.

In a mixing bowl, combine the soy sauce, hoisin sauce, honey, rice vinegar, brown sugar, minced garlic, minced ginger, sesame oil, and optional chili flakes. Whisk everything together until smooth.

Pour the prepared marinade evenly over the chuck roast, making sure every inch of the meat is coated.

Cover the slow cooker or pot with a lid, and cook on low for 6–8 hours.

Once cooked, carefully remove the roast from the cooker and transfer it to a cutting board. Tent with aluminum foil to keep warm while it rests for about 15–20 minutes.

While the roast is resting, pour the remaining cooking liquid into a saucepan. Bring it to a simmer over medium heat.

In a small bowl, mix cornstarch with a little water to make a slurry. Slowly stir this into the simmering cooking liquid, cooking until the sauce thickens into a glossy glaze—about 2–3 minutes.

Slice the rested chuck roast against the grain into tender pieces. Drizzle the thickened glaze generously over the beef.

For a delightful finishing touch, sprinkle sesame seeds and chopped green onions over the glazed roast.