Begin by liberally seasoning your beef chuck roast with salt, black pepper, and garlic powder. Ensure every side is well-coated for maximum flavor.

Slice your large onion and place the rings at the bottom of the slow cooker.

In a separate bowl, combine the beef broth, brown gravy mix, and Worcestershire sauce. Whisk until smooth.

Cover the slow cooker and set it to cook on low for 8 hours.

If you prefer a thicker gravy, mix equal parts cornstarch and water to create a slurry and whisk it into the gravy.

When ready to serve, place the prepared mashed potatoes on plates and generously top with the shredded beef and gravy mixture.