Cook the Pasta: Bring a large pot of salted water to a boil. Add pasta and cook until just tender. Drain and set aside while everything else comes together.
Season the Chicken: Place chicken pieces in a bowl. Sprinkle with salt, pepper, and flour. Toss gently until lightly coated. This helps thicken the sauce later.
Sauté the Vegetables: Heat butter in a large deep skillet over medium heat. Add onion, carrot, and celery. Stir often until soft and lightly golden, about five minutes.
Add Herbs and Chicken: Stir in rosemary and parsley. Add chicken to the pan and cook until lightly browned on all sides. The chicken does not need to cook through at this stage.
Deglaze the Pan: Pour in white wine and scrape up any browned bits from the bottom. Let it simmer for two minutes so the alcohol cooks off and the flavor deepens.
Build the Sauce: Slowly pour in chicken broth while stirring. Bring the mixture to a gentle simmer and cook until the sauce thickens slightly and the chicken turns tender.
Finish the Dish: Add cooked pasta and frozen peas. Stir everything together and simmer for a few minutes until peas warm through and the sauce coats the pasta evenly.
