Heat the olive oil in a large pot over medium-high heat. Once hot, add the beef stew meat and sear until browned on all sides, about 5-7 minutes. Remove the meat and set aside.
Reduce the heat to medium, add the chopped onions, celery, and garlic to the pot, and sauté for another 8-10 minutes, until the onions become soft.
Add the cajun seasoning, kosher salt, black pepper, and dried thyme. Stir well to combine for about 10 seconds.
Return the beef chunks to the pot, then pour in the beef broth, diced tomatoes (with their juices), and the Worcestershire sauce. Lay the bay leaves on top.
Bring the mixture to a boil, reduce the heat to low, cover the pot, and let it simmer for about 1 hour, until the beef begins to fall apart.
Add the mixed vegetables and potato to the pot. Stir well, cover, and continue simmering for another 20-25 minutes or until the vegetables and potatoes are tender.
Check the seasoning and adjust with more salt and pepper if necessary. Remove the bay leaves before serving.
Serve hot, garnished with fresh parsley if desired.