Step 1: Brown the Ground Beef
Heat the olive oil in a large Dutch oven or stockpot over medium-high heat. Once the oil is shimmering, add the ground beef. Use a wooden spoon or spatula to break the meat apart as it cooks. Brown the beef until no pink remains, which should take about 7-10 minutes. This browning step is crucial as it creates the fond (the browned bits on the bottom of the pot) which adds immense depth of flavor to the soup.

Step 2: Drain and Sauté the Aromatics
Once the beef is browned, carefully drain off any excess grease, leaving about a tablespoon in the pot for flavor. Return the pot to the heat. Add the chopped yellow onion, carrots, and celery (this trio is known as a mirepoix). Sauté the vegetables for 5-7 minutes, stirring occasionally, until the onion becomes translucent and the vegetables begin to soften. Add the minced garlic and cook for another minute until fragrant. Be careful not to burn the garlic.

Step 3: Build the Broth
Add the tomato paste to the pot. Stir it into the beef and vegetable mixture and cook for 1-2 minutes. “Toasting” the tomato paste like this deepens its flavor and removes any raw, tinny taste. Now, pour in the Worcestershire sauce to deglaze the pan, scraping up any of those flavorful browned bits from the bottom of the pot with your spoon.

Step 4: Combine and Simmer
Pour in the beef broth and the can of undrained diced tomatoes. Add the diced potatoes, dried thyme, dried oregano, bay leaf, salt, and black pepper. Stir everything together until well combined. Bring the soup to a boil, then immediately reduce the heat to low. Cover the pot and let the soup simmer gently for 25-30 minutes, or until the potatoes and carrots are tender when pierced with a fork.

Step 5: Add Final Vegetables and Finish
Once the potatoes are tender, remove the bay leaf. Stir in the frozen corn and frozen green beans. Increase the heat slightly and continue to cook for another 5-10 minutes, or until the frozen vegetables are heated through and tender. Using frozen vegetables at the end keeps them vibrant and prevents them from becoming mushy.

Step 6: Taste and Serve
Taste the soup and adjust the seasonings as needed. It may need another pinch of salt or a few more grinds of black pepper. Ladle the hot soup into bowls, garnish with fresh parsley if desired, and serve immediately.