Creating Slow Cooker Korean Beef is straightforward if you follow these simple steps:

1. Prepare the Beef: Cut the beef chuck roast into 1-inch pieces and place them in the slow cooker.
2. Make the Sauce: In a bowl, whisk together the soy sauce, brown sugar, sesame oil, minced garlic, minced ginger, and black pepper until well combined.
3. Combine: Pour the sauce over the beef in the slow cooker, ensuring all pieces are coated.
4. Cook: Cover the slow cooker and cook on low for 7-8 hours or on high for 3-4 hours, until the beef is tender.
5. Thicken the Sauce (Optional): If you prefer a thicker sauce, remove about 1/4 cup of the cooking liquid and mix it with cornstarch in a small bowl. Return this mixture to the slow cooker and cook on high for an additional 30 minutes.
6. Serve: Once cooked, shred the beef with two forks or leave it in chunks. Serve over cooked rice or noodles.
7. Garnish: Top with sliced green onions and sesame seeds, if desired.

These steps will guide you in creating this incredible dish effortlessly.