Cook the Pasta: Bring a large pot of heavily salted water to a boil. Add the pasta and cook according to package directions until al dente (with a firm bite). Before you drain, reserve at least 1 cup of the starchy pasta water. Drain the pasta and set aside.

Prepare and Cook the Salmon: While the pasta is cooking, pat the salmon fillets completely dry with paper towels. Sprinkle 1 ½ tablespoons of the Cajun seasoning evenly over the top side of the salmon fillets, pressing it in gently to adhere.

Sear the Salmon: Heat the olive oil in a large, heavy-bottomed skillet over medium-high heat. Once the oil is shimmering, carefully place the salmon fillets in the pan, seasoned-side down. Sear for 4-5 minutes without moving, until a dark, blackened crust forms. Flip the salmon, reduce the heat to medium, and cook for another 2-4 minutes, or until the salmon is cooked to your liking but still slightly pink in the center. Transfer the cooked salmon to a plate and set aside.

Start the Sauce: In the same skillet, melt the butter over medium heat. Add the chopped onion and cook for 3-4 minutes, until softened. Add the minced garlic and chopped sun-dried tomatoes and cook for another minute until the garlic is fragrant, stirring constantly.

Build the Creamy Sauce: Stir in the remaining ½ tablespoon of Cajun seasoning. Pour in the can of diced tomatoes with their juice, using your spoon to scrape up any flavorful browned bits from the bottom of the pan. Bring the sauce to a gentle simmer.

Make it Luscious: Reduce the heat to low and slowly stir in the heavy cream until the sauce is smooth. Let it gently warm through for a minute, but do not let it boil. Stir in the grated Parmesan cheese until it has melted completely into the sauce.

Combine and Finish: Add the cooked pasta to the skillet with the sauce. Toss to combine, coating every piece of pasta. If the sauce is too thick, stir in the reserved pasta water, a few tablespoons at a time, until it reaches your desired consistency.

Add the Salmon: Gently flake the cooked salmon into large, bite-sized chunks, discarding any grey protein (the albumen) that may have cooked out. Add the flaked salmon to the pasta and gently fold it in, trying not to break up the pieces too much.

Serve: Taste the pasta and season with additional salt and pepper if needed. Divide the Cajun Salmon Pasta among bowls, garnish with fresh parsley, an extra sprinkle of Parmesan cheese, and serve immediately with fresh lemon wedges on the side for squeezing.