Step 1: Preheat Your Oven

• Preheat your oven to 350°F (175°C).
• Grease a 9×13-inch baking dish with butter or cooking spray to prevent sticking.

Step 2: Cook the Spaghetti

• Bring a large pot of salted water to a boil.
• Cook the spaghetti until al dente, according to the package instructions.
• Drain and set aside.

Step 3: Sauté the Vegetables

• In a large skillet, melt 2 tablespoons of butter over medium heat.
• Add the diced onion and sliced mushrooms. Sauté for 5-7 minutes, or until the onions are translucent and the mushrooms are tender.
• Add the minced garlic and cook for another 1-2 minutes until fragrant.
• Remove from heat and set aside.

Step 4: Make the Creamy Sauce

• In the same skillet, melt the remaining 1 tablespoon of butter over medium heat.
• Sprinkle in the flour, stirring constantly for about a minute to make a roux.
• Gradually pour in the chicken broth while whisking to prevent lumps. Cook until the mixture thickens.
• Stir in the garlic-flavored cream cheese, letting it melt into the sauce.
• Slowly add the half-and-half, stirring constantly, until the sauce is creamy and thickened.
• Mix in the fresh parsley, Italian seasoning, salt, and pepper. Remove from heat.

Step 5: Combine Ingredients

• In a large mixing bowl, combine the cooked spaghetti, diced turkey, sautéed vegetables, and creamy sauce. Stir until evenly coated.

Step 6: Assemble the Casserole

• Transfer the mixture to the prepared baking dish, spreading it out evenly.
• Sprinkle the mozzarella cheese and grated Parmesan cheese evenly over the top.

Step 7: Bake the Casserole

• Cover the dish with foil to prevent the cheese from browning too quickly.
• Bake in the preheated oven for 30 minutes.
• Remove the foil and bake for another 10-15 minutes, or until the cheese is bubbly and golden.

Step 8: Serve

• Let the casserole rest for a few minutes before serving.
• Garnish with additional fresh parsley for a burst of color and flavor.
• Serve hot and enjoy!