1. Grab a large bowl and combine the ground beef, chopped onions, eggs, stuffing mix, milk, Italian seasoning, parsley, ketchup, salt, and pepper. Mix with a wooden spoon or use your hands, I use my hands.
2. Line your slow cooker with heavy-duty aluminum foil or two layers of regular aluminum foil. Spray the foil with vegetable spray to keep it from sticking.
3. Scoop the meat mixture into your slow cooker and mold it into the desired loaf shape.
4. Cover and cook on high for 3 hours or 6 hours on low.
5. Combine the slow cooker meatloaf glaze ingredients. Whisk the ketchup, brown sugar, dry mustard, and Worcestershire sauce until smooth.
6. After baking, check the temperature, it's safe to eat when it reaches (160°F) = (71°C). Lift the foil with the meatloaf out of the slow cooker. Place the meatloaf on a serving dish. Spread the meatloaf glaze over the meatloaf.
7. Serve with mashed potatoes! Enjoy.