Heat the vegetable oil in a large pot over medium heat. Add the ground beef and cook until browned, breaking it up with a spoon as it cooks.
Add the diced onion and minced garlic to the pot. Cook for 3 to 4 minutes until the onion softens.
Stir in the cubed potatoes, sliced carrots, and sliced parsnips. Cook for another 2 minutes to coat the vegetables lightly with the beef drippings.
Pour in the beef broth and add the Worcestershire sauce and dried rosemary. Season with salt and black pepper.
Bring the mixture to a boil, then reduce the heat to low. Cover the pot and simmer for 45 minutes, stirring occasionally, until the potatoes, carrots, and parsnips are tender.