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