Place beans into a large bowl, fill the bowl with water, and cover the bowl with a cloth. Allow to soak overnight.

Drain and rinse beans; place into a large soup pot. Add turkey legs, onion, and bay leaves to the pot, cover with water, then bring to a boil over medium heat. Reduce heat to medium-low; simmer for 3 hours.

Remove bay leaves and discard. Remove turkey legs from broth, separate meat from the bones and tendons, and return meat to broth.

Stir in celery, carrots, diced tomatoes, Italian seasoning, salt, and pepper; simmer until celery and carrots are tender, about 1 hour.

Serve soup in bowls and sprinkle each serving with about 1 teaspoon Parmesan cheese.