In a large bowl, combine the ground beef, garlic powder, onion powder, sea salt, Italian seasoning, black pepper, egg, bread crumbs, Worcestershire sauce, and whole milk. Mix well using your hands for the best texture, or use a stand mixer with a paddle attachment if you prefer.

Shape the mixture into golf ball-sized meatballs, about 2 tablespoons each, making around 24 meatballs. Dampen your hands with water to make rolling easier.

In a large Dutch oven or heavy-bottom stock pot, heat 2 tablespoons of olive oil over medium-high heat. Brown the meatballs on all sides, working in batches if necessary. They don’t need to be fully cooked at this stage. Once browned, set the meatballs aside on a plate.

If needed, deglaze the pan with a few tablespoons of beef stock. Add the remaining tablespoon of olive oil to the pot, then add the diced onion, celery, and carrots. Cook for about 5 minutes, stirring occasionally, until the vegetables begin to soften.

Stir in the minced garlic and cook for an additional minute until fragrant. Then, add the tomato paste and thyme, mixing well.

Return the browned meatballs to the pot, along with the beef stock and beef bouillon. Bring the mixture to a boil over high heat, then reduce to a simmer.

Add the potatoes and green beans to the pot. Cover with a tight-fitting lid and simmer for 20 minutes, or until the vegetables are tender and the meatballs reach an internal temperature of 160°F (71°C). If you prefer firmer green beans, add them 10 minutes after the potatoes.

In a small bowl, mix the cornstarch and cold water until smooth. Stir this cornstarch slurry into the stew and cook over low heat for an additional 5-7 minutes, or until the stew has thickened.

Serve the hearty stew garnished with fresh parsley, alongside some crusty bread or buttered egg noodles.