Bring a large pot of slightly salted water to a boil. Add linguine and cook for 8 to 10 minutes or until al dente. Drain, reserving ½ cup of the pasta water.
While the pasta is cooking, in a large bowl, combine the shrimp with olive oil and cajun seasoning; toss to combine.
Heat a large skillet set over medium-high heat. Add the shrimp in a single layer and cook 3 to 5 minutes, flipping once, until opaque on each side. Transfer the cooked shrimp to a plate and repeat with the remaining shrimp.
Reduce the heat to medium and melt butter. Add garlic and allow it to brown for 30 seconds, until fragrant. Gradually whisk in the heavy cream and lemon zest. Cook 1 to 2 minutes, whisking constantly, until incorporated. Stir in the Parmesan and simmer for 1 to 2 minutes, until slightly thickened. Stir in a few tablespoons of reserved pasta water if you want a thicker sauce. Taste and season with salt and pepper, as desired.
Add the pasta to the pan with the sauce and stir to combine. Serve immediately topped with the shrimp, lemon wedges and parsley, for garnish.
NOTE: If desired, you can make your own Cajun seasoning by combining the following spices: 1 teaspoon garlic powder, 1 1 teaspoon paprika, ¼ teaspoon onion powder, ¼ teaspoon oregano, ¼ teaspoon cayenne pepper, ¼ teaspoon salt, ⅛ teaspoon black pepper, one pinch red chili flakes. NOTE: You can adjust the amount of cajun seasoning depending on your taste. Use 2 teaspoons for less cajun flavor or 4 to 5 teaspoons for more cajun flavor.NOTE: You can use any kind of pasta noodles for this recipe. However, long noodles like spaghetti, fettuccine and linguine work the best.