Add the cooked ground beef, potatoes, carrots, onions, and garlic to a 5-quart or larger slow cooker.
In a small bowl whisk together the tomato paste, water, salt, pepper, onion powder and oregano. Pour this mixture over everything in the slow cooker. Stir.
Cover and cook on LOW for 6-7 hours, without opening the lid during the cooking time.
Serve with buttered sandwich bread.