Preheat the oven to 375 degrees. Coat an 9-inch baking dish with cooking spray.
Cook the cavatappi noodles per package instructions to al dente, in a large pot of well-salted boiling water.
Make the rue, in a large saucepan, melt the butter over medium heat; stir in the flour, smoked paprika, garlic powder, and onion powder until well combined and cook for 1-2 minutes, stirring constantly. Very slowly add in the milk, whisking constantly, until well combined; cook and stir until bubbly.
Finish the sauce, by reducing heat to low and gradually add the 1 cup of cheddar cheese, 1 cup of Monterey Jack cheese, and American cheese slices; whisk until melted. Stir in the Dijon mustard then season with sea salt and freshly cracked pepper, to taste.
Taste the sauce and add more seasonings if needed. Add the cooked & drained noodles to the sauce.
Toss to coat evenly then pour into the prepared baking dish. Top with the remaining cheddar and Monterey Jack cheese evenly over the macaroni and cheese.
Bake the macaroni and cheese by placing into the oven to bake for 15 minutes. Turn the oven to broil and cook, watching very carefully, for 2-3 minutes, or until the cheese is melted and golden brown.
Remove from the oven and sprinkle the top with parsley, if desired. Serve and enjoy.