Add beef cubes to your slow cooker carefully.
Pour in beef broth and soy sauce slowly.
Add hoisin sauce and sesame oil next.
Add garlic, ginger, and brown sugar gently.
Add carrots, bell pepper, and green onions.
Season with salt, pepper, and red pepper flakes.
Cover and cook on low for six hours.
Cook ramen noodles per package and drain.
Add noodles and spinach to slow cooker carefully.
Stir gently and add rice vinegar before serving.
Serve Slow Cooker Beef Ramen Noodles Recipe hot.
Garnish with green onions before serving if desired.