1. Cook the pasta al dente according to package directions in salted water. Transfer the cooked pasta to a colander over the sink and run cold water over it until cool.2. Prepare the Cajun spice mixture by combining all of the ingredients in a small bowl.
4. Melt a tablespoon of butter in a large sauté pan over medium-high heat. Once hot, add the chicken and cook for 5-6 minutes, stirring occasionally, until cooked through then transfer to a medium bowl.
5. Add another tablespoon of butter to the sauté pan. Once melted, add the shrimp and cook for 2-3-minutes then flip and cook another 2-3 minutes until cooked through and slightly browned. Transfer to the bowl with the chicken.
6.Melt the remaining butter in the sauté pan. Add the bell pepper and onion, sprinkle with 1/4 teaspoon kosher salt, and cook for 5 minutes tossing occasionally. Add the garlic and cook for one minute then transfer to the bowl with the chicken and shrimp.
7. Pour the chicken broth into the pan and scrape with a wooden spoon or spatula to deglaze.8. Reduce the heat to medium, then add the heavy whipping cream, the remaining Cajun spice mixture, and the Parmesan cheese. Stir in the fire roasted tomatoes and cook for three minutes stirring often.
9. Add the pasta, chicken, shrimp, and veggies, stirring to combine. Cook for 2-3 minutes to warm everything back up then serve garnished with shredded Parmesan and sliced scallions. For additional heat, sprinkle with red pepper flakes.