Italian Wedding Soup with Turkey Meatballs

Name: Italian Wedding Soup with Turkey Meatballs
Ingredients: 12 ounces ground turkey meat (preferably white meat); 1/3 cup whole-wheat bread crumbs; 2 egg whites; 2 tablespoons chopped fresh parsley; 2 garlic cloves, minced; 1 3/4 teaspoons kosher salt, plus more for seasoning; 1/2 teaspoon dried oregano; 1/4 teaspoon freshly ground black pepper, plus a few grinds; 2 tablespoons olive oil; 1 large onion, diced; 2 stalks celery, sliced lengthwise and cut thinly crosswise; 2 carrots, peeled and chopped; 8 cups chicken stock (low-sodium, if possible); 3 cups kale, stems removed and leaves sliced thin; 2 cups escarole, core removed and leaves sliced thin (if you can't find escarole, just substitute with more kale); Parmesan cheese for serving