Creating Cheesy Pesto Chicken Casserole is simple if you follow these steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C).
2. Prepare the Chicken: In a large mixing bowl, combine the shredded chicken and pesto sauce, mixing until the chicken is well-coated.
3. Cook the Pasta: In a separate pot, cook the pasta according to package instructions. Drain and set aside.
4. Combine Ingredients: In the bowl with the chicken and pesto, add the cooked pasta, heavy cream, garlic powder, salt, and black pepper. Mix well until fully combined.
5. Add Cheese: Stir in half of the mozzarella and Parmesan cheese, reserving the other half for topping.
6. Transfer to Casserole Dish: Pour the mixture into a greased 9×13 inch casserole dish, spreading it evenly.
7. Top with Cheese: Sprinkle the remaining mozzarella and Parmesan cheese over the top.
8. Add Tomatoes: If using, scatter the halved cherry tomatoes on top for added flavor and a pop of color.
9. Bake: Place the casserole in the preheated oven and bake for 30-35 minutes, or until the cheese is bubbly and golden.
10. Cool Slightly: Once baked, remove from the oven and let it cool for about 5 minutes before serving.

These steps will guide you in creating this incredible casserole effortlessly. It’s a straightforward process that yields delicious results!