Serve with some crusty bread and a green salad for a hearty meal.
Bring broth to a simmer in a Dutch oven (do not boil). Keep warm over low heat.
Soak the bread in milk for 5 minutes, and squeeze moisture from the bread. Combine the moistened bread, ground beef, minced onion, 1/4 cup grated cheese, 1/4 cup chopped parsley, salt, and pepper in a bowl.
Shape the mixture into approximately 24 (1 1/2-inch) meatballs. Add the raw meatballs and shredded carrot to the warm broth, and bring to a boil. Reduce heat, and simmer for 10 minutes. Stir in the cooked orzo and simmer for an additional 2 minutes.
Sprinkle with the remaining grated cheese and chopped parsley. Serve immediately.