01 - Melt butter in a large pot or deep skillet over medium heat. Add onions, carrots, and celery. Sauté for 4–5 minutes until vegetables begin to soften.
02 - Stir in 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 chicken broth, then add 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 orzo is al dente and the sauce thickens.
06 - Stir in heavy cream, cooked chicken, and frozen peas. Simmer for 3–5 more minutes until chicken is heated through and 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.