Chicken, Spinach and Black Bean Enchiladas with Greek Yogurt Sauce

Last night I tried a new variation to my chicken enchiladas.  We both liked the flavors.  I thought the filling was dry and not heated through enough, so I might increase the length of time in the oven and put some sauce inside the enchiladas as well.

Filling:
Cubed or shredded cooked chicken (2 cups - 3 lbs)
1 can black beans, rinsed
1 cup chopped baby spinach
Black pepper to taste
3/4 cup cheese
10 tortillas

Sauce:
1/4 cup flour
2 T butter
1 can chicken broth (about 1-1/2 cups)
3/4 tsp salt
1/4 tsp pepper
3/4 cup Greek yogurt or sour cream
2-4 T chili powder

Spray a 13x9 baking dish with vegetable oil.  Pre-heat the oven to 375 degrees.  Combine cut chicken, spinach, and pepper.  Gently stir in black beans.  For the sauce, whisk butter and flour to make a roux and add chicken broth, salt, pepper and chili powder.  Stir while thickening, on medium high heat.  When bubbling, stir in Greek yogurt or sour cream.  Ensemble the enchiladas by warming up tortillas, adding 1/3 cup of filling and 2 tsp shredded cheese.  Once the tortillas are laid in the baking dish, pour remaining cheese and filling and cover with sauce.  Cover with aluminum foil and bake for 20-25 minutes.

Adapted from: Goodman, Katie. Good Life Eats. "Chicken, Black Bean, and Spinach Enchiladas". 13. Jan 2010.