Baked Cheesy Deliciousness

So I bought a pound of rigatoni in the bulk bins at Rainbow Grocery because I haven't ever tried cooking creamy pasta with this type of pasta and apparently it's perfect because it's fluted and "picks up that cream so incredibly well". Right, so I needed to try and found a recipe by Giada De Laurentiis on Food Network and here's the delicious results with a few additions and changes:
Ingredients:

• 1 4 oz. stick of butter
• 1/2 c. plus 2 tbsp. flour
• 3/4 qt. whole milk
• 1 c. grated mozzarella
• 2 large carrots, cut into bite-size pieces
• 10 white button mushrooms, sliced
  
• 2 cooked chicken breasts, cut into bite-size pieces
• 1 lb. uncooked rigatoni
• Salt and pepper to taste
  

1. Preheat your oven to 425 degrees F
   
2. Melt butter in a large saucepan (enough to fit more than a quart of liquid), add the flour and whisk until smooth.
3. Whisk in the milk and keep stirring until smooth, keep cooking until the cream coats the back of a spoon and you can draw your finger along the back of the spoon and the cream stays separated. Remove from heat.
   
4. Stir in half the cheese and all the chicken, carrots and mushrooms, set aside.
5. Cook rigatoni in boiling water for 5 minutes, the rigatoni should be undercooked as it will continue cooking in the oven.
   
6. Drain pasta and mix in with the cream sauce.
   
7. Pour into a large and deep baking dish (13x9 inch is recommended, or smaller if you want to split them up), sprinkle remaining cheese and bake for 25 minutes.

Serve hot and steaming. Yum.