Chicken Enchilada Casserole **PREP Chicken***
Boil the chicken for 20 minutes and shred- using Bosch/Kitchen Aid/Mixer. Preheat oven to 350 degrees. Grease a 9x13 baking dish. Optional: Char tortillas over gas burner until lightly charred in spots. Cut in half. In a saucepan on medium heat add 2 T. of butter and 2 T. of olive oil. Sauté the onions for 2-3 minutes. Sprinkle with ¼ C. of flour (or GF thickener) Stir, it will be thick. Whisk in the liquid broth mixture. Bring to a boil then reduce heat to low and simmer until thickened. Stir in sour cream. Remove from heat. Pour ½ C. of the sauce on the bottom of the 9x13, spread. Add shredded chicken into the remaining sauce. Layer 10 tortilla halves, cut edges flush to outside of dish, then fill the rest in the middle. Top evenly with ⅓ Chicken mixture, cheese. Layer 3 times ending with cheese. Cover with foil and bake for 20 minutes. Top with diced tomato and avocado.