Bring a pot of water to a boil. Boil pasta until al dente. Set aside.
Meanwhile, add the sausage to a dutch oven or large skillet with sides. Cook for about 3 minutes per side. Set aside.
Add 1 teaspoon of oil and the shrimp to the dutch oven. Cook for 2 minutes per side, and set aside. (They will be slightly undercooked and that's ok. You don't want to overcook them)
Add the remaining 2 teaspoons of oil to the dutch oven along with the onions, bell pepper, and celery. Saute for 7 minutes.
Add garlic, paprika, cayenne, salt, nutmeg, and cornstarch to the dutch oven. And stir well. Continue stirring while you slowly add in the milk, stirring constantly. Once the milk has been incorporated, cook for two minutes, stirring very often until the mixture thickens. Add in 1 cup of the cheddar cheese along with the reserved sausage and shrimp. Stir until combined.
Transfer mixture to an 8 inch square baking dish (or leave in pot if oven-safe). Top with parmesan cheese and remaining 1/4 cup cheddar. Bake for 15 to 20 minutes until cheese is bubbly and lightly browned. Optional: broil for 1 to 2 minutes to brown the cheese a little more.
Remove from oven, and enjoy!
*You can alternately use an oven safe french or dutch oven to make the sauce, and bake it in the same to keep from having to wash multiple dishes.
*Use mild sausage and/or cut back on the cayenne pepper for a more mild dish.
*Recipe was tested using gluten free chickpea pasta (and nutrition facts were calculated with this, too). Any pasta will work
*Based on this recipe
Recipe from Living Well Kitchen https://blog.memeinge.com/cajun-mac-and-cheese/