Prepare fettuccine according to package directions; drain pasta, and set aside.
Cook sausage in a large Dutch oven over medium heat 10 minutes or until browned; remove sausage, and drain, reserving 1 tablespoon drippings in Dutch oven. Set sausage aside.
Melt butter in drippings in Dutch oven over medium heat. Add shrimp, and cook 5 minutes or just until shrimp turn pink. Remove shrimp, and keep warm.
Add onion and next 3 ingredients; cook, stirring constantly, over medium heat 10 minutes. Stir in Cajun seasoning and flour. Cook over medium heat, 1 minute, stirring constantly. Gradually stir in chicken broth. Bring to a boil over medium-high heat, stirring occasionally. Boil 1 minute. Reduce heat to medium-low, and stir in heavy cream; cook over medium-low heat 8 minutes or until mixture simmers. Add pasteurized cheese cubes, sausage, and shrimp, stirring until cheese melts.
Stir in chopped green onions, Parmesan cheese, and chopped fresh parsley. Serve over hot cooked fettuccine.
Note: For testing purposes only, we used Velveeta for pasteurized prepared cheese product. Freeze shrimp and andouille pasta in 3 (8 1/4- x 5 1/4- x 1-inch) disposable foil pans covered with aluminum foil. Place in zip-top plastic freezer bags. Freeze up to 1 month, if desired. Remove from freezer bag, and bake, covered, at 350° for 1 hour and 15 minutes. Or thaw in refrigerator overnight, and bake, covered, at 350° for 45 minutes. Each pan contains about two servings.
Substitute 3 cups chopped cooked chicken for shrimp. While the fettuccine cooks, start the sausage.