Fill a large pot with water and add kosher salt. Bring it to a boil. Add the fettuccine pasta and cook until al dente according to package instructions. Reserve ⅔ cup of pasta water before draining. Set aside.
½ pound (8 ounces) pasta, ½ tablespoon kosher salt
While the pasta is cooking, heat butter and olive oil in a cast iron skillet or stainless steel skillet over medium heat. Season salmon with Cajun seasoning on all sides. Sear salmon for 4-5 minutes on each side. Transfer to a plate and set aside to rest.
1 tablespoon butter, 1 tablespoon olive oil, 1 pound salmon fillet, 2 tablespoons Cajun seasoning
In the same skillet, melt the remaining 2 tablespoons of butter. Sauté onion, red bell pepper, and garlic for about 5-7 minutes or until softened. Stir in Cajun seasoning and tomato paste and cook for an additional 1-2 minutes.
2 tablespoons butter, ½ large yellow onion, 1 red bell pepper, 3 cloves garlic, ½ tablespoon Cajun seasoning, 1 tablespoon tomato paste
Reduce heat to low and whisk in the reserved pasta water and light cream. Let the sauce simmer for 5 minutes to thicken slightly. Remove from heat and stir in grated parmesan cheese until melted.
½ cup light cream, 1 cup parmesan cheese
Toss the cooked pasta with the alfredo sauce. Plate with the salmon on top or flake the salmon and mix it into the pasta. Serve immediately and enjoy!