1 small onion, grated
1/3 cup chopped fresh Italian parsley
1 large egg
1 teaspoon minced garlic
1 teaspoon salt
1 slice fresh white bread, crust trimmed, bread torn into small pieces
1/2 cup grated Parmesan
8 ounces ground beef
8 ounces ground pork
Freshly ground black pepper
12 cups low-sodium chicken broth
1 pound curly endive, coarsely chopped (1 pound of escarole would be a good substitution)
2 large eggs
2 tablespoon freshly grated Parmesan, plus extra for garnish
Salt and freshly ground black pepper
To make the meatballs: Stir the first 6 ingredients in a large bowl to blend. Stir in the cheese, beef and pork. Using 1 1/2 teaspoons for each, shape the meat mixture into 1-inch-diameter meatballs. Place on a baking sheet.
To make the soup: Bring the broth to a boil in a large pot over medium-high heat. Add the meatballs and curly endive and simmer until the meatballs are cooked through and the curly endive is tender, about 8 minutes. Whisk the eggs and cheese in a medium bowl to blend. Stir the soup in a circular motion. Gradually drizzle the egg mixture into the moving broth, stirring gently with a fork to form thin stands of egg, about 1 minute. Season the soup to taste with salt and pepper.
Ladle the soup into bowls and serve. Finish soup with parmesan cheese if desired.