Heat the olive oil in a large skillet over medium heat. Add the beef stew meat and cook until browned on all sides, about 5 minutes. Transfer the beef to the slow cooker.
Add the chopped onion and minced garlic to the same skillet. Cook for 2 minutes until the onion softens, then stir in the tomato paste.
Place the potatoes and carrots into the slow cooker. Add the browned beef on top.
Pour the beef broth into the slow cooker. Stir in the dried thyme, salt, and black pepper.
Cover and cook on low for 8 hours until the beef is tender and the vegetables are soft.
Stir the stew gently before serving to distribute the flavors.