Melt the butter over medium high heat in a large skillet.
Add the onion, garlic, carrots, and celery and cook for 4-5 minutes until fragrant and softened.
Add in the sherry and stir until it is reduced by half, about 1 minute.
Add in the orzo, sage, thyme, rosemary, salt, and pepper and stir. Pour in the broth. Bring to a boil, then reduce heat to medium low and cook for 15-16 minutes, stirring occasionally, until most of the broth has been absorbed and the orzo is tender.
Stir in the peas and shredded chicken until warmed through. Add the half and half and stir.
Let it sit for 5 minutes with the heat off (it will thicken) before serving with fresh chopped parsley, if desired.