Creating the Simple Baked Tuscan Chicken Casserole is easy if you follow these steps:

1. Preheat Oven: Preheat your oven to 375°F (190°C).
2. Cook Pasta: If using pasta, cook according to package directions and set aside.
3. Sauté Vegetables: In a large skillet, heat olive oil over medium heat. Add minced garlic, red bell pepper, and sun-dried tomatoes. Sauté for about 5 minutes, or until the vegetables soften.
4. Combine Chicken and Spinach: In a large bowl, mix the sautéed vegetables with shredded chicken and chopped spinach.
5. Add Cheeses and Herbs: Fold in ricotta cheese, half of the mozzarella, grated Parmesan cheese, oregano, basil, salt, and pepper until well combined.
6. Mix in Pasta: If using, add the cooked pasta to the mixture and stir until evenly coated.
7. Transfer to Baking Dish: Pour the mixture into a greased 9×13-inch baking dish. Spread evenly.
8. Top with Cheese: Sprinkle the remaining mozzarella cheese over the top.
9. Bake: Place in the preheated oven and bake for 30-35 minutes or until the cheese is bubbly and golden.
10. Cool and Serve: Remove from the oven, let it cool for 5 minutes, and serve warm.

By following these steps, you’ll create a mouthwatering casserole that perfectly brings together the elements of Tuscan cuisine.