Allow the steaks to come to room temperature. Generously season all sides of the meat with the cajun or blackened seasoning.
Bring a large pot of salted water to a boil for the fettuccine. Cook the fettuccine until al dente according to package instructions, typically about 12 minutes. Reserve ½ to 1 cup of the pasta water, then drain the pasta and set aside.
While the pasta cooks, preheat a cast iron skillet over high heat. Add the butter to the pan. Once the butter has melted, add the steaks and sear for 2-4 minutes per side until medium-rare (130 to 135 degrees F) when tested with a digital meat thermometer. Remove and rest on a cutting board. **Keep in mind the steaks temperature will rise about 5 degrees as it rests.**
Heat another skillet with a stick of butter over medium-high heat. Add in the sun dried tomatoes and minced garlic. Sauté for 30-60 seconds until fragrant. Slowly add the heavy cream while whisking. Lower the heat to a simmer and cook for 5 to 10 minutes until thickened a bit, stirring occasionally. Stir in the diced tomatoes along with the grated parmesan and Gorgonzola cheese. Add pepper, Italian seasoning, and salt.
Add the cooked fettuccine noodles to the sauce and toss to coat. If the sauce looks too thick, add some of the pasta water to loosen it up a bit.
Use a sharp knife to slice steak into thin strips. Top the pasta with the steak and garnish with chopped fresh parsley and additional grated parmesan cheese, if desired. Enjoy!