Place butternut squash in a 350° oven and bake about 1 hour or until done.
Remove peel and seeds; discard.
Cut into ¾” cubes.
Set aside.
Meanwhile, sprinkle both sides of chicken with Italian seasoning to cover well.
Use more if needed.
Grill over high heat until cooked through.
Slice chicken down and cut into cubes.
Set aside.
Meanwhile, fill a large stock pot with water and bring to a boil.
Add gluten free pasta and cook according to package directions.
Drain pasta in colander and set aside.
Meanwhile, place butter in a large sauce pan or Dutch oven.
Add onions and red bell pepper and sauté about 5 minutes.
Add garlic and sauté another minute.
Add cream, half-and-half, parmesan cheese and 1 ½ cups Italian cheese blend.
Stir to combine and heat over low to medium heat until thickened.
Stir in salt, pepper and nutmeg.
Combine grilled chicken, baked butternut squash, drained penne pasta and cheese sauce.
Pour into a 10x15” glass baking dish that’s been sprayed with cooking spray.
Sprinkle generously with additional Italian seasoning, salt and pepper.
Cover with foil.
Bake at 350° for about 30-45 minutes or until casserole is hot and bubbly.
Sprinkle remaining 1 ½ cups of Italian cheese blend over top of casserole.
Bake an additional 5-10 minutes, or until cheese melts.
Garnish with additional Italian seasoning and fresh parsley, if desired.