Creating Turkey Tetrazzini is easy if you follow these simple steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Cook Pasta: Boil the spaghetti or linguine according to package instructions until al dente. Drain and set aside.
3. Sauté Vegetables: In a large skillet, melt 4 tablespoons of butter over medium heat. Add the diced onion and sliced mushrooms. Sauté until softened, about 5-7 minutes. Stir in minced garlic and cook for an additional minute.
4. Make the Sauce: Sprinkle the flour over the sautéed vegetables and stir well to combine. Gradually add the chicken broth while whisking to avoid lumps. Allow the mixture to simmer for about 2-3 minutes until it thickens.
5. Add Cream and Seasoning: Stir in the heavy cream, dried thyme, salt, black pepper, and paprika. Continue to cook for another 2-3 minutes until heated through.
6. Combine Ingredients: In a large mixing bowl, combine the cooked pasta, shredded turkey, and frozen peas. Pour the sauce over the mixture and stir until everything is well coated.
7. Transfer to Baking Dish: Grease a 9×13 inch baking dish. Pour the mixture into the dish and spread it evenly.
8. Top with Cheeses: Sprinkle the grated Parmesan cheese and shredded mozzarella cheese evenly over the top.
9. Bake: Place the baking dish in the preheated oven and bake for 25-30 minutes until the top is golden and bubbly.
10. Rest and Serve: Once baked, remove from the oven and let it cool for 5-10 minutes before serving.

These steps will guide you in creating this incredible Turkey Tetrazzini effortlessly.