Preheat oven to 350°F (175°C).
Cook the penne pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium-high heat.
Add the chicken pieces to the skillet and season with salt, black pepper, and dried Italian seasoning. Cook for 6-8 minutes until the chicken is cooked through and lightly browned. Remove chicken from skillet and set aside.
In the same skillet, add diced onion and minced garlic. Sauté for 2-3 minutes until fragrant and translucent.
Add diced red bell pepper, zucchini, and sliced mushrooms to the skillet. Cook for 5-6 minutes until vegetables are tender.
Reduce heat to medium-low and add butter to the skillet. Once melted, pour in the heavy cream and whole milk, stirring to combine.
Simmer the cream mixture for 3-4 minutes, stirring frequently until it begins to thicken slightly.
Stir in the grated Parmesan cheese until melted and smooth. Season the Alfredo sauce with additional salt and black pepper to taste.
Return the cooked chicken to the skillet and stir to coat with the sauce.
Add the cooked penne pasta to the skillet and gently toss to combine all ingredients evenly.
Transfer the entire mixture into a 9×13 inch freezer-safe baking dish. Allow to cool completely before covering tightly with aluminum foil or plastic wrap.
To freeze: Place the dish in the freezer for up to 3 months.
To bake from frozen: Preheat oven to 350°F (175°C). Remove plastic wrap if used and cover with foil. Bake for 45-50 minutes or until heated through and bubbly. Remove foil during the last 10 minutes of baking to brown the top slightly.
Garnish with freshly chopped parsley before serving.