01 - Melt the butter in a large pot or deep skillet over medium heat. Add the diced onions, carrots, and celery. Sauté for 4–5 minutes, stirring occasionally, until the vegetables begin to soften.
02 - Stir in the minced garlic and cook for 1 minute until fragrant, being careful not to let it brown.
03 - Sprinkle the flour evenly over the sautéed vegetables and stir to coat thoroughly. Cook for 1 minute to eliminate the raw flour taste and form a light roux.
04 - Slowly whisk in the chicken broth, followed by the whole milk, stirring constantly to prevent lumps. Bring the mixture to a gentle simmer.
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 keep the orzo from sticking, until the pasta is al dente and the sauce has thickened.
06 - Stir in the heavy cream, cooked chicken, and frozen peas. Continue simmering for 3–5 minutes until the chicken is heated through and the peas are tender. Taste and adjust seasoning as needed.
07 - Remove the pot from the heat and let it sit for 2–3 minutes so the sauce finishes thickening. Garnish with additional parsley and serve warm.