Creating Cheesy Buffalo Chicken Pasta Bake is a breeze if you follow these step-by-step instructions:

1. Preheat the Oven: Set your oven to 350°F (175°C) to get it ready for baking.
2. Boil the Pasta: In a large pot of salted water, cook the penne pasta until al dente, typically about 8-10 minutes. Drain and set aside.
3. Prepare the Sauce: In a large mixing bowl, combine the buffalo sauce, cream cheese, ranch dressing, garlic powder, onion powder, salt, and pepper. Whisk until smooth.
4. Mix Chicken and Vegetables: Fold in the shredded chicken and diced celery into the sauce mixture, ensuring everything is evenly coated.
5. Combine Pasta and Sauce: Add the cooked pasta into the chicken mixture and mix well to combine.
6. Transfer to Baking Dish: Lightly grease a 9×13-inch baking dish with olive oil. Pour the Buffalo chicken pasta mixture into the dish, spreading it evenly.
7. Add Cheese Toppings: Sprinkle the shredded cheddar and mozzarella cheese on top of the pasta mixture, ensuring it’s generously covered.
8. Bake in the Oven: Place the baking dish in the preheated oven. Bake for 30-35 minutes, or until the cheese is bubbling and golden brown.
9. Garnish: Once baked, remove it from the oven and let it cool for a few minutes. Garnish with fresh parsley if desired before serving.

Following these steps will yield an incredible Cheesy Buffalo Chicken Pasta Bake that is sure to impress those who get to enjoy it!