Melt butter in a large soup pot over medium heat. Add onion and cook for 2 minutes. Add carrots and celery and cook an additional 2 minutes. Sprinkle flour over mixture and cook 2 more minutes.
Mix chicken broth, cannellini beans, ham, Dijon mustard, Italian seasoning, and crushed red pepper flakes into the pot. Bring to a boil. Reduce heat and simmer for 15 minutes.
Add tortellini and cook 5 minutes. Stir in half-and-half and turn stove off. Let soup sit for 5 minutes. Ladle soup into bowls and garnish with Parmesan cheese and fresh parsley.
