Start by heating 1 tablespoon of olive oil in a large nonstick skillet over medium-high heat. Once it’s hot, toss in the chopped onion along with ¼ teaspoon each of salt and pepper. Let it cook, stirring often, until the onions are soft and golden, about 6 minutes. Add in the garlic and cook for another minute, just until it smells amazing.

Scoop half of that onion mixture into a large mixing bowl—that’s going to help flavor our meatballs. The other half goes straight into the slow cooker.

Now into the slow cooker: pour in the broth, carrots, zucchini, peas, green beans, corn, celery, diced tomatoes, another ¼ teaspoon each of salt and pepper, and the Italian seasoning. Give it a gentle stir to combine.

Back to the mixing bowl. Add the ground chicken, Panko breadcrumbs, Parmesan, egg, and the remaining salt and pepper. Mix everything together just until combined—don’t overdo it or the meatballs can get tough. Shape into meatballs about 1 ¼ inches in size.

Heat your remaining tablespoon of olive oil in the same skillet (no need to wash it). Add the meatballs and brown them on all sides, about 5–6 minutes total. No need to cook them all the way through—they’ll finish in the slow cooker.

Carefully nestle the browned meatballs into the soup. Don’t stir them in, just gently submerge them.

Cover and cook on HIGH for 3–4 hours until the meatballs are fully cooked (165°F internal temp) and the veggies are perfectly tender.

When you're ready to serve, sprinkle over some fresh chopped parsley and a generous handful of Parmesan if you like. Ladle it up and dig in!