Bring a large pot of salted water to a boil.

In a skillet, heat the olive oil over medium heat and add the chopped onion. Sauté until the onion becomes translucent, about 3 minutes.

Stir in the minced garlic and cook for an additional minute.

Add the crawfish tails to the skillet and cook for 3 to 5 minutes until heated through.

Pour in the heavy cream and mix well.

Stir in the grated Parmesan cheese and Cajun seasoning, mixing until smooth.

Drain the pasta and add it to the skillet, tossing it in the sauce.

Season with salt and pepper to taste, then garnish with chopped parsley before serving.