Italian Tortellini and Meatball Soup

8 oz. ground beef chuck¼ c. grated parmesan cheese, plus more for topping¼ c. chopped fresh parsley1 large egg, lightly beaten1 garlic clove, gratedKosher salt and black pepper2 T. olive oil3 carrots, diced3 celery stalks, diced4 c. chicken broth1 (9-oz.)…