Chicken, Mushroom, & Wild Rice Soup

2 (6-oz.) packages long-grain and wild rice mix
10 cups chicken broth, divided
3 tablespoons butter
1 cup sliced fresh mushrooms
1 cup chopped onion
1 cup chopped celery
1/4 cup butter
1/2 cup all-purpose flour
1/2 cup half-and-half
2 tablespoons dry white wine
2 cups cooked shredded chicken breasts
Garnishes: fresh parsley leaves, freshly cracked pepper

1.) Bring rice, 4 cups chicken broth, and 1 seasoning packet from rice mix to a boil in a saucepan over medium-high heat. Cover, reduce heat to low, and simmer 20 minutes or until liquid is absorbed and rice is tender. (Reserve remaining seasoning packet for another use.)

2.) Meanwhile, melt 3 Tbsp. butter in a large skillet over medium heat; add mushrooms, onion, and celery, and cook, stirring often, 10 to 12 minutes or until tender.

3.) Melt 1/4 cup butter in a Dutch oven over medium heat; whisk in flour, and cook, whisking constantly, 1 minute, or until thickened and bubbly. Gradually whisk in remaining 6 cups broth, and cook, stirring often, 8 to 10 minutes or until slightly thickened.

4.) Whisk in half-and-half and wine. Stir in mushroom mixture, chicken, and rice. Cook, stirring occasionally, 5 to 10 minutes or until thoroughly heated. (Do not boil.) Garnish, if desired.