Prep the Tongue: Rinse the beef tongue under cold water. Trim any excess fat or muscle, and score the surface lightly.
Season: Rub the tongue with salt, black pepper, and garlic powder. Place it in the slow cooker with the onion slices.
Add Liquids and Herbs: Pour the broth over the tongue until it is fully covered. Add the bay leaves, thyme, parsley, and any additional spices you prefer.
Slow Cook: Cover and cook on low for 8 hours until the meat is tender.
Peel and Slice: Once cooked, remove the tongue, let it cool slightly, then peel off the outer layer of skin. Slice the meat against the grain.
Serve: Enjoy the beef tongue slices with a side of the reduced cooking liquid as a sauce, or use as desired.