In a large pot of boiling salted water, cook the fettuccine according to package instructions until al dente. Drain and set aside, reserving a small cup of pasta water.
In a mixing bowl, toss the shrimp with Cajun seasoning until evenly coated.
In a large skillet, heat the olive oil over medium-high heat. Add the seasoned shrimp and cook for 2-3 minutes on each side, or until they turn pink and opaque. Remove the shrimp from the skillet and set aside.
In the same skillet, lower the heat to medium and add minced garlic. Sauté for about 30 seconds until fragrant. Pour in the heavy cream and stir, allowing it to simmer lightly for 3-5 minutes.
Gradually stir in the grated Parmesan cheese until it's completely melted and well combined. If the sauce is too thick, add some reserved pasta water until desired creaminess is achieved.
Add the cooked fettuccine, sun-dried tomatoes, and sautéed shrimp to the Alfredo sauce. Toss everything together gently until the pasta is fully coated in sauce.
Season with salt, pepper, and optional red pepper flakes to taste. Remove from heat and stir in chopped parsley for a fresh touch.
Notes
Serve in bowls with extra parsley and Parmesan cheese on top. Add lemon wedges for extra flavor.