Place the beef chuck roast pieces into your slow cooker.
In a bowl, whisk together the beef broth, garlic, ginger, soy sauce, oyster sauce, brown sugar, sesame oil, and chili flakes if using. Pour this mixture over the beef in the slow cooker.
Add the white parts of the green onions to the slow cooker. Cover and cook on low for 6-8 hours, or on high for 3-4 hours, until the beef is tender.
About 30 minutes before serving, add the julienned carrots and red bell pepper to the slow cooker. Stir gently.
Meanwhile, cook the ramen noodles separately according to the package instructions, usually 3-4 minutes in boiling water, then drain.
Once the vegetables are tender and the meat is cooked, stir in the cooked ramen noodles.
Serve the beef ramen hot, garnished with the green parts of the onions, sesame seeds, and fresh herbs.
