Step 1

Melt butter in a large saucepan over medium heat. Stir in the onion, celery and carrots and saute for 5 minutes. Add the mushrooms and saute for 2 more minutes.

Step 2

Add the flour and whisk together.

Step 3

Gradually pour in the chicken broth, whisking constantly until combined. Bring just to a boil, reduce heat to low and let simmer for 20 minutes.

Step 4

Add the rice, chicken, salt, parsley, mustard powder, and black pepper. Allow to heat through, then pour in the half-and-half. Let simmer for 10 minutes. Do not boil.