Add chicken breasts, cauliflower, Italian seasoning, and broth. Bring to a boil, then simmer for 20 minutes, flipping chicken halfway.
Transfer chicken to a bowl, shred into bite-sized pieces, and set aside.
Blend cooked cauliflower and 1/2 cup broth until smooth. Return to pot with shredded chicken, peas, and half and half. Warm for 3-4 minutes, then season to taste.
Notes
For a lighter soup, use less half and half or skip it entirely.