Turkey and Rice Bake

1 14-ounce can chicken broth 1 cup finely chopped onions 1/2 cup finely chopped carrots 1/2 cup finely chopped celery 1 tbsp dried parsley 1/2 cup evaporated skim milk or half-and-half 3 tbsp cornstarch 1 tsp dry mustard 1/4 tsp ground black pepper 3 cups cooked diced...