Baked Cheesy Chicken Penne

Ingredients :

6 tablespoons butter, plus more for baking dishes
kosher salt and black pepper
1 pound penne rigate (I used a 14.5 oz box of Ronzoni Smart Taste Penne Rigate)
1 teaspoon olive oil
2 boneless, skinless chicken breast halves (about 8 ounces each), halved horizontally (I used some leftover cooked chicken)
1/2 cup plus 2 tablespoons flour
6 garlic cloves, finely minced
6 cups whole milk
10 ounces white or cremini mushrooms, trimmed and thinly sliced (I used 8 oz of button mushrooms)
1 cup sliced oil-packed sun-dried tomatoes, drained
1 1/2 cups shredded provolone (6 ounces) (I used an italian blend that had provolone in it)
1 1/2 cup freshly grated Parmesan (about 6 ounces)

How to make it :

Preheat oven to 400. Butter two shallow 2-quart baking dishes. If you’re going to freeze one, use a disposable foil pan. In a large pot of boiling salted water, cook pasta 3 minutes short of al dente; drain pasta and set aside.
While pasta is boiling, heat oil over medium-high heat in a large skillet. Season chicken with salt and pepper; cook until opaque throughout, 3 to 5 minutes per side. Halve each piece lengthwise, then thinly slice crosswise. While chicken pan is still hot, toss the mushrooms in and saute until golden brown (3-4 minutes). Use a little extra olive oil if needed.(Since I used left over chicken, I just cooked the mushrooms in the olive oil)
In a 5-quart Dutch oven or heavy pot , melt butter over medium. Add flour and garlic; cook, whisking, 1 minute. While whisking constantly, gradually add milk; bring to a simmer. Keep whisking frequently as sauce thickens, about 1 minute more. Add mushrooms and tomatoes; cook 1 minute. Take the pan off the heat and and gradually stir in provolone and 1/2 cup Parmesan.
Add chicken and pasta to pot; season with salt and pepper to taste. Divide pasta mixture between baking dishes. If freezing, place remaining parmesan cheese in a zip-top baggie. If cooking, sprinkle on top.
Bake, uncovered, until top is golden and bubbling, about 25 minutes. Let stand 5 minutes before serving.
Freezer instructions:

To freeze, prepare through step 4 and then let pasta cool. Cover pan well with plastic wrap. Place extra cheese in baggie (for topping) on top and then cover entire pan well with foil. Freeze for up to 3 months. To bake, preheat oven to 400. Remove foil and plastic from pan and set cheese baggie aside. Place foil back on pan and bake for about 1 1/2 hours. Remove foil, stir pasta, and top with cheese. Return pan to oven and bake for an additional 15 minutes (I only did 10 minutes) or until mixture is hot and bubbly throughout.