Heat a large pot over medium-high heat. Once hot, add the olive oil and then the beef to the pot. Brown the ground beef, breaking it up as it cooks.
Add the diced onion, diced celery, and minced garlic to the pot and cook for 3-4 minutes until the onion starts to become translucent.
Add the tomato paste, potatoes, frozen vegetables, crushed tomatoes, balsamic vinegar, beef broth, Italian seasoning, salt, bay leaf, and thyme to the pot. Stir until well combined.
Bring the soup to a boil and then reduce to a simmer. Cover and simmer for 20-25 minutes. Give the soup a taste and adjust the seasoning as needed.
Serve with a little chopped green onion and fresh parsley with a grilled cheese on the side!