01 - Melt butter in a large pot or deep skillet over medium heat. Add onions, 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 flour over the vegetables and stir to coat evenly. Cook for 1 minute to remove the raw flour taste.
04 - Slowly whisk in the chicken broth, then add the milk. Bring to a gentle simmer, stirring constantly to prevent lumps.
05 - Add orzo, thyme, parsley, salt, and pepper. Stir well. Reduce heat to medium-low and simmer uncovered for 10–12 minutes, stirring occasionally to prevent sticking, until the orzo is al dente and the sauce thickens.
06 - Stir in the heavy cream, cooked chicken, and frozen peas. Simmer for 3–5 more minutes until the chicken is heated through and the peas are tender. Adjust seasoning as needed.
07 - Remove from heat and let sit for 2–3 minutes to allow the sauce to thicken further. Garnish with extra parsley and serve warm.