Chicken and Rice Casserole

1-1/2 c cooked chicken, diced
2 c cooked rice
2 carrots, peeled and finely chopped
1-1/2 c milk
1 c chicken broth
1/2 c parmesan cheese
1/2 c bread crumbs
3/4 c frozen peas, thawed
1/4 c all-purpose flour
6 TBS butter, divided
salt and pepper

Preheat oven to 400 degrees. Lightly grease 9x13 dish.
In large sauce pan over medium heat, melt 4 TBS butter. Whisk in flour and cook 1-2 minutes until smooth.
While whisking continuously, gradually pour in milk and broth and stir until completely incorporated.
Add chicken, rice, carrots and peas to broth mixture.
Season with salt and pepper.
Transfer to baking dish and sprinkle parmesan cheese and bread crumbs evenly over top.
Cut up remaining butter into small pieces and dot over bread crumbs.
Bake 20-25 minutes until bubbly and golden brown.