Heat the olive 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 onion and garlic to the pot. Cook for 3 to 4 minutes until the onion softens.
Stir in the carrots, parsnips, potatoes, thyme, bay leaves, salt, and pepper. Cook for another 2 minutes to combine the flavors.
Pour in the beef broth and bring the mixture to a boil.
Add the rinsed barley. Reduce the heat to low, cover the pot, and simmer for 50 to 60 minutes until the barley is tender and the vegetables are soft. Stir occasionally and add a splash of water if the stew thickens too much.