Cook your desired type of pasta in a pot of salted boiling water according to the package directions. Make sure your pasta is al dente and not overcooked.
Preheat oven to 350°F and prepare a 9x13-inch baking dish.
Prepare the base:
Melt butter in a large skillet over medium-high heat.
Add shallots (or green onions) and celery and cook, stirring for 5 minutes. Add garlic and cook until fragrant.
Add mushrooms and cook until just tender. Stir in flour and cook for 1 minute.
Add the liquid:
Pour in the chicken stock and half cream. Cook for 1 minute. Then stir in cream cheese, sour cream, and Italian seasoning. Remove from the heat. Make sure the sour cream is well mixed; otherwise, you will end up with lumps of sour cream after baking. Season to taste with salt and pepper, if needed.
Assemble:
Combine the cooked pasta, turkey, and ½ cup of mozzarella with the prepared sauce.
Transfer the mixture into the baking dish and top with the remaining mozzarella and parmesan cheese.
Bake:
Bake for 25 minutes or until the cheese is melted and bubbly.
Cool for 10 minutes before serving.
Serve garnished with basil or chopped parsley.
Notes
If you do not have cream cheese, you can use condensed cream of chicken or mushroom soup. In that case, reduce the flour by half.