Cook the spaghetti according to the package directions. Drain well before adding to the sauce.
While the pasta is cooking, cook the ground sausage in a large skillet until no longer pink. Add the taco seasoning and water and stir to combine. Stir in the marinara sauce, add the spaghetti, and toss to coat.
Stuff the shells with the spaghetti and top with tomatoes, Mexican cheese, a sprinkle of parmesan, and parsley.
Don't Pre-Assemble: Assemble these tacos as you need them, so the taco shells don’t get soggy.
Super Cheesy: You can fill the tacos and serve immediately, or place them in a hot oven till the cheese has melted for an extra-cheesy experience.
The Best Shells: Old El Paso Stand ‘N Stuff taco shells have flat bottoms, so they are easier to place on a baking sheet or plate and stuff. But you can use any taco shells you like!
Storing: The leftover pasta and sauce can be stored in airtight containers in the refrigerator for up to seven days.
Reheating: Reheat pasta and sauce in a covered skillet over low to medium heat, stirring occasionally and adding a splash of water if the dish seems dry.