Heat a large pot over medium-high heat with 1 tablespoon olive oil. Add the ground beef, break it up, and cook until browned, about 6–8 minutes. Drain excess fat, leaving about 1 tablespoon in the pot for flavor.
Add remaining olive oil, then onion, carrots, and celery. Sauté until onions are translucent, about 5 minutes. Add garlic and cook 30 seconds. Stir in tomato paste and cook 1 minute.
Add diced tomatoes with juices, broth, potatoes (if using), thyme, oregano, and bay leaf. Bring to a boil, then reduce to a simmer for about 20 minutes until vegetables are tender.
Stir in green beans and corn; simmer 5–7 more minutes. Taste and season with salt and pepper. Remove bay leaf and stir in parsley before serving.
Notes
For a thicker soup, mash a few cooked potato pieces against the pot side and stir.
Substitute ground turkey or chicken if you prefer; add a little extra oil to compensate for lower fat.
This soup freezes well—cool completely and freeze up to 3 months.
Use frozen vegetables to save time and reduce prep.