Sauté aromatics: In a big pot, heat olive oil over medium heat until the oil shimmers. Add onions, celery, carrot and garlic and sauté 4-6 minutes, until onion is translucent.
Build the soup: Add in vegetable broth, along with dried parsley, basil, oregano, and bay leaf. Bring to a boil. Reduce heat to low or medium-low, as needed to establish a rapid simmer. Simmer for about 10 minutes to soften the vegetables.
Cook the pasta and greens: Stir in the dry pasta and cook at a gentle boil until tender. Timing will depend on pasta shape. I recommend starting to check around the 8 minute mark, but it can take up to 15 minutes. Add extra time as needed. (It will take longer than the cook time listed on the pasta packaging because we are simmering rather than boiling.) For very tender greens, add the baby kale in at the same time as the pasta. For fresher greens, add in the baby kale when the pasta is almost fully cooked so it has just about 1-2 minutes to wilt.
Finishing touches: Add back in the cooked meatballs and simmer another minute or so to heat everything through. Taste the broth and adjust salt and pepper to preference. Enjoy!