Follow these easy steps to create your own High-Protein Spinach Artichoke Chicken Casserole:

1. Preheat the Oven: Preheat your oven to 350°F (175°C) and grease a 9×13 inch casserole dish with cooking spray or olive oil.
2. Prepare the Chicken: In a large mixing bowl, combine the cooked shredded chicken with the artichoke hearts and chopped spinach, ensuring everything is mixed well.
3. Create the Sauce: In a separate bowl, whisk together the Greek yogurt, mozzarella cheese, Parmesan cheese, garlic, onion powder, garlic powder, salt, black pepper, and red pepper flakes (if using).
4. Combine the Mixtures: Pour the cheese mixture over the chicken and vegetables. Stir until everything is well coated.
5. Transfer to Casserole Dish: Spoon the mixture into the greased casserole dish, spreading it out evenly.
6. Add Topping: If desired, sprinkle breadcrumbs over the top and add extra mozzarella cheese for a cheesy topping.
7. Bake: Place the casserole in the preheated oven and bake for 30-35 minutes, or until heated through and the top is golden and bubbly.
8. Cool Slightly: Remove from the oven and let it cool for about 5 minutes before serving.

These simple steps will guide you to create a delightful dish that is guaranteed to impress!