Place cubed chicken breasts, onion, celery, chicken broth, half and half, garlic powder, thyme, salt, pepper, and carrots inside the crockpot. Cook for 4 hours on high, or 6 on low.
In the last 30 minutes, prepare your favorite biscuits. Also, combine water and corn starch until combined. Add the mixture into the crockpot along with frozen peas. Cook for an additional 30 minutes and serve with fresh parsley and biscuits.