Step 1

Make Chicken and Broth first. Combine chicken, celery, onion, parsley, thyme, bay leaves, salt, and pepper in a large pot. Add water to cover and bring to a boil. Reduce heat and simmer 45 minutes. Remove chicken and let cool. Discard skin and remove chicken, shredding it into bite-sized pieces. Strain broth and reserve 4 cups.

Step 2

Preheat oven to 400 degrees and spray a 13X9-inch baking dish with cooking spray.

Step 3

In a large skillet, melt 1/4 cup butter over medium-high heat. Add celery, carrots, onion, and mushrooms. Cook for 5 to 6 minutes, until vegetables are tender. Stir in peas. Set aside.

Step 4

Melt remaining 1/4 cup butter in a Dutch oven. Add flour and cook, stirring constantly, for 2 minutes.

Step 5

Gradually add chicken broth, whisking constantly to avoid lumps. Add cream and continue to cook for 3 to 4 minutes, whisking constantly.

Step 6

Add reserved chicken, celery/onion mixture, thyme, salt, and pepper. Check and make sure it is seasoned enough and add more salt if necessary.

Step 7

Pour into prepared dish.

Step 8

In a medium bowl, combine biscuit mix, cheeses, and milk. Stir just until combines. Take a spoon and drop large spoonfuls evenly over filling.

Step 9

Bake 18 to 23 minutes, or until biscuits are golden brown.