01 - Melt butter in a large pot or deep skillet over medium heat. Add diced onions, carrots, and celery. Sauté for 4 to 5 minutes until the vegetables begin to soften.
02 - Stir in minced garlic and cook for 1 minute until fragrant.
03 - Sprinkle flour over the vegetables and stir to coat evenly. Cook for 1 minute to remove any raw flour taste.
04 - Slowly whisk in chicken broth, then pour in the milk. Bring to a gentle simmer, stirring constantly to prevent lumps.
05 - Add orzo pasta, dried thyme, dried parsley, salt, and black pepper. Stir well to combine. Reduce heat to medium-low and simmer uncovered for 10 to 12 minutes, stirring occasionally to prevent sticking, until the orzo is al dente and the sauce has thickened.
06 - Stir in heavy cream, cooked chicken, and frozen peas. Continue simmering for 3 to 5 minutes until the chicken is heated through and the peas are tender. Adjust salt and pepper to taste.
07 - Remove from heat and let sit for 2 to 3 minutes so the sauce can finish thickening. Garnish with extra dried parsley and serve warm.