Preheat your oven to 350°F (175°C).
Lightly grease a 9 x 5-inch loaf pan.
Combine ground beef, onion, bell pepper, celery, cheddar cheese, and garlic in a large bowl.
Mix well but avoid overhandling.
In a medium bowl, mix bread crumbs, Lipton onion soup mix, parsley, warm water, and ketchup.
Combine thoroughly.
Add the mixture to the meat and vegetable blend.
Mix with your hands until evenly combined.
Press the mixture evenly into the prepared loaf pan.
Place the pan on a baking sheet for easy transfer.
Bake the meatloaf for about 60 minutes or until a meat thermometer reads 160°F (71°C).
Let it rest for a few minutes before slicing.