01 - In a large pot or deep skillet, melt the butter over medium heat. Add the diced onions, carrots, and celery. Sauté for 4 to 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 everything well. 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 keep the sauce smooth and 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 to 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 diced chicken, and frozen peas. Continue to simmer for 3 to 5 more minutes until the chicken is heated through and the peas are tender. Taste and adjust the seasoning as needed.
07 - Remove the pot from the heat and let it sit for 2 to 3 minutes so the sauce can finish thickening. Garnish with additional parsley and serve warm.