Add the butter and olive oil to a large soup pot.
Once butter has melted, add onions and sauté until translucent but not browned.
Add salt, black pepper, and red pepper (if using). Stir well.
Add carrots and celery, stir well, and sauté for a minute.
Add shredded chicken. Stir well.
Add bone broth.
Bring to a boil, then turn down to medium, cover, and allow to simmer for 15 minutes.
Ladle into bowls and serve.