For the sauce:
3 Tbs butter
3 Tbs flour
1 cup milk
1 cup chicken broth
1/2 tsp cayenne pepper, or to taste
Salt and freshly ground pepper to taste

For the hash:
2 Tbs butter
1 medium onion, finely chopped
1 red or yellow bell pepper, seeded and finely chopped
8 oz mushrooms, thinly sliced
3 Tbs chopped fresh parsley
Salt and freshly ground pepper to taste
2 cups diced potatoes, boiled until tender
and drained
2 cups diced cooked chicken
Chopped chives for garnish

For the sauce, melt the butter in a saucepan over moderate heat. Stir in
the flour and cook 3 minutes, stirring frequently. Add the milk, chicken
broth, cayenne, salt, and pepper and bring to a simmer. Cook for 5 minutes,
stirring frequently.

For the hash, melt the butter in a large skillet over moderate heat. Saute
the onion and bell pepper until tender, about 5 minutes. Add the mushrooms,
parsley, salt, and pepper and cook an additional 10 minutes. Add the
potatoes, chicken, and sauce, and transfer to a buttered shallow baking
dish. Bake in a preheated 400°F oven for 30 to 40 minutes, until it is
bubbling and the top is golden brown. Garnish with chopped chives.