- Place chicken between 2 sheets of waxed paper and pound until about ¼ to ½ inch thick. Sprinkle with salt, pepper, and flour. Quickly sauté in ¼ cup butter until golden. Remove to plate and add remaining ¼ cup butter to pan and sauté onion, garlic, and mushrooms slowly until cooked but not browned. Stir in flour, salt, pepper, chicken stock, and wine. Cook until thickened, about 5 minutes. Stir in mashed avocados and ½ cup cheese.
- Arrange chicken breasts in glass baking dish. Top with sauce, remaining cheese, and green chiles, if desired. Bake at 350ºF for 10 minutes. Serves 8.