Making Super Tender Slow Cooker Teriyaki Beef is an enjoyable process if you follow these easy steps:

1. Prepare the Beef: Cut the beef chuck roast into 1-inch cubes. Trim any excess fat for a leaner dish.

2. Mix the Sauce: In a bowl, combine soy sauce, brown sugar, rice vinegar, sesame oil, minced garlic, grated ginger, and red pepper flakes. Whisk until the sugar dissolves.

3. Add to Slow Cooker: Place the cubed beef in the slow cooker. Pour the teriyaki sauce mixture over the beef, ensuring it’s well-coated.

4. Slow Cook: Cover the slow cooker and cook on low for 6-8 hours or on high for 3-4 hours, until the beef is incredibly tender.

5. Thicken the Sauce: Once the beef is cooked, remove it from the slow cooker and set aside. In a small bowl, combine cornstarch and water to create a slurry. Pour this into the slow cooker and stir until the sauce thickens, which should take about 5-10 minutes.

6. Combine Beef and Sauce: Return the tender beef to the slow cooker, mixing it with the thickened sauce to ensure it is evenly coated.

7. Adjust Seasoning: Taste your teriyaki beef and adjust seasoning if needed, adding a little more soy sauce or sugar if you like.

8. Serve: Prepare rice or noodles according to package instructions for a perfect pairing.

9. Garnish: Before serving, sprinkle sliced green onions and sesame seeds over the beef for added visual appeal and flavor.

10. Enjoy: Serve the beef over rice or noodles, and enjoy the incredible flavors of your Super Tender Slow Cooker Teriyaki Beef!